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Lessons 
Worksheets 
Games 

HSGCO.A.1 
Know precise definitions of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc. 
Geometry Definitions 
Perpendicular
and Parallel Lines Geometric Definitions 

HSGCO.A.2 
Represent transformations in the plane using, e.g., transparencies and geometry software; describe transformations as functions that take points in the plane as inputs and give other points as outputs. Compare transformations that preserve distance and angle to those that do not (e.g., translation versus horizontal stretch). 
Translations 

HSGCO.A.3 
Given a rectangle, parallelogram, trapezoid, or regular polygon, describe the rotations and reflections that carry it onto itself. 

HSGCO.A.4 
Develop definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments. 
Define Translations 

HSGCO.A.5 
Given a geometric figure and a rotation, reflection, or translation, draw the transformed figure using, e.g., graph paper, tracing paper, or geometry software. Specify a sequence of transformations that will carry a given figure onto another. 
Translations 

HSGCO.B.6 
Use geometric descriptions of rigid motions to transform figures and to predict the effect of a given rigid motion on a given figure; given two figures, use the definition of congruence in terms of rigid motions to decide if they are congruent. 
Congruent Triangles 1 

HSGCO.B.7 
Use the definition of congruence in terms of rigid motions to show that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent. 
Congruency Postulates 


HSGCO.B.8 
Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow from the definition of congruence in terms of rigid motions. 

HSGCO.C.9 
Prove theorems about lines and angles. Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment?s endpoints. 

HSGCO.C.10 
Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180?; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point. 

HSGCO.C.11 
Prove theorems about parallelograms. Theorems include: opposite sides are congruent, opposite angles are congruent, the diagonals of a parallelogram bisect each other, and conversely, rectangles are parallelograms with congruent diagonals. 

HSGCO.D.12 
Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line. 

HSGCO.D.13 
Construct an equilateral triangle, a square, and a regular hexagon inscribed in a circle. 
Compass Construction 2 
Code 
Standard 
Lessons 
Worksheets 
Games 
HSGSRT.A.1 HSSRT.AG1b.

Verify experimentally the properties of dilations given
by a center and a scale factor: 

HSGSRT.A.2 
Given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides. 
Defining similarity through anglepreserving transformations 

HSGSRT.A.3 
Use the properties of similarity transformations to establish the AA criterion for two triangles to be similar. 
Similar triangles 1 

HSGSRT.B.4 
Prove theorems about triangles. Theorems include: a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem proved using triangle similarity. 

HSGSRT.B.5 
Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures. 
Solve problems with similar and
congruent triangles 

HSGSRT.C.6 
Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles. 

HSGSRT.C.7 
Explain and use the relationship between the sine and cosine of complementary angles. 
Trig Functions in right triangles  
HSGSRT.C.8 
Use trigonometric ratios and the Pythagorean Theorem to solve right triangles in applied problems. 

HSGSRT.D.9 
(+) Derive the formula A = 1/2 ab sin(c) for the area of a triangle by drawing an auxiliary line from a vertex perpendicular to the opposite side. 
Nonright triangle proofs 

HSGSRT.D.10 
(+) Prove the Laws of Sines and Cosines and use them to solve problems. 

HSGSRT.D.11 
(+) Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and nonright triangles (e.g., surveying problems, resultant forces). 
Law of cosines 
Code 
Standard 
Lessons 
Worksheets 
Games 
HSGC.A.1 
Prove that all circles are similar. 
Define similarity through angle preserving transformations  
HSGC.A.2 
Identify and describe relationships among inscribed angles, radii, and chords. Include the relationship between central, inscribed, and circumscribed angles; inscribed angles on a diameter are right angles; the radius of a circle is perpendicular to the tangent where the radius intersects the circle. 
Central, inscribed, and circumscribed
angles 

HSGC.A.3 
Construct the inscribed and circumscribed circles of a triangle, and prove properties of angles for a quadrilateral inscribed in a circle. 

HSGC.A.4 
(+) Construct a tangent line from a point outside a given circle to the circle. 
Construct tangent 

HSGC.B.5 
Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius, and define the radian measure of the angle as the constant of proportionality; derive the formula for the area of a sector. 
Radians
and Arc Length 
Code 
Standard 
Lessons 
Worksheets 
Games 
HSGGPE.A.1 
Derive the equation of a circle of given center and radius using the Pythagorean Theorem; complete the square to find the center and radius of a circle given by an equation. 
Pythagorean theorem and the equation of
a circle 

HSGGPE.A.2 
Derive the equation of a parabola given a focus and directrix. 
Parabola intuition 1 

HSGGPE.A.3 
(+) Derive the equations of ellipses and hyperbolas given the foci, using the fact that the sum or difference of distances from the foci is constant. 
Explore foci
of an Ellipse 

HSGGPE.B.4 
Use coordinates to prove simple geometric theorems algebraically. For example, prove or disprove that a figure defined by four given points in the coordinate plane is a rectangle; prove or disprove that the point (1, ?3) lies on the circle centered at the origin and containing the point (0, 2). 

HSGGPE.B.5 
Prove the slope criteria for parallel and perpendicular lines and use them to solve geometric problems (e.g., find the equation of a line parallel or perpendicular to a given line that passes through a given point). 

HSGGPE.B.6 
Find the point on a directed line segment between two given points that partitions the segment in a given ratio. 

HSGGPE.B.7 
Use coordinates to compute perimeters of polygons and areas of triangles and rectangles, e.g., using the distance formula. 
Coordinate Plane word problems 
Code 
Standard 
Lessons 
Worksheets 
Games 
HSGGMD.A.1 
Give an informal argument for the formulas for the circumference of a circle, area of a circle, volume of a cylinder, pyramid, and cone. Use dissection arguments, Cavalieri's principle, and informal limit arguments. 

HSGGMD.A.2 
(+) Give an informal argument using Cavalieri's principle for the formulas for the volume of a sphere and other solid figures. 

HSGGMD.A.3 
Use volume formulas for cylinders, pyramids, cones, and spheres to solve problems. 

HSGGMD.B.4 
Identify the shapes of twodimensional crosssections of threedimensional objects, and identify threedimensional objects generated by rotations of twodimensional objects. 
Cross sections of 3D objects Rotate 2D to make 3D 
Code 
Standard 
Lessons 
Worksheets 
Games 
HSGMG.A.1 
Use geometric shapes, their measures, and their properties to describe objects (e.g., modeling a tree trunk or a human torso as a cylinder). 

HSGMG.A.2 
Apply concepts of density based on area and volume in modeling situations (e.g., persons per square mile, BTUs per cubic foot). 

HSGMG.A.3 
Apply geometric methods to solve design problems (e.g., designing an object or structure to satisfy physical constraints or minimize cost; working with typographic grid systems based on ratios). 
Geometric Shapes word problems 
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