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Lesson Plans and Worksheets for Grade 7

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More Lessons for Grade 7

Common Core For Grade 7

Examples, videos, and solutions to help Grade 7 students learn how to find the areas of triangles and simple polygonal regions in the coordinate plane.

### New York State Common Core Math Grade 7, Module 3, Lesson 19

Download worksheets for Grade 7, Module 3, Lesson 19

### Lesson 19 Student Outcomes

### Closing

Vocabulary:

quadrilateral, parallelogram, trapezoid, rectangle, square, altitude and base of a triangle, semicircle, diameter of a circle.

Area formulas:

Area of parallelogram = Base x Height

Area of rectangle = Base x Height

Area of a triangle = 1/2 x Base x Height

Area of a trapezoid = 1/2 x (Base 1 + Base 2) x Height

Area of a circle = π x r^{2}

Lesson 19 Classwork

Example: Area of a Parallelogram

The coordinate plane below contains figure P, parallelogram ABCD.

a. Write the ordered pairs of each of the vertices next to the vertex points.

b. Draw a rectangle surrounding figure P that has vertex points of A and C. Label the two triangles in the figure as S and T.

c. Find the area of the rectangle.

d. Find the area of each triangle.

e. Use these areas to find the area of parallelogram ABCD.

The coordinate plane below contains figure R, a rectangle with the same base as the parallelogram above.

f. Draw triangles S and T next to R so that you have a rectangle that is the same size as the one you created on the first coordinate plane.

g. Find the area of rectangle R.

h. What do figures R and P have in common?

Exercises

1. Find the area of triangle ABC.

2. Find the area of quadrilateral ABCD two different ways.

3. The area of quadrilateral ABCD = 12 sq. units. Find x.

4. The area of triangle ABC = 14 sq. units. Find the length of side BC.

5. Find the area of triangle ABC.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

Lesson Plans and Worksheets for Grade 7

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 7

Common Core For Grade 7

Examples, videos, and solutions to help Grade 7 students learn how to find the areas of triangles and simple polygonal regions in the coordinate plane.

• Students find the areas of triangles and simple polygonal regions in the coordinate plane with vertices at grid
points by composing into rectangles and decomposing into triangles and quadrilaterals.

quadrilateral, parallelogram, trapezoid, rectangle, square, altitude and base of a triangle, semicircle, diameter of a circle.

Area formulas:

Area of parallelogram = Base x Height

Area of rectangle = Base x Height

Area of a triangle = 1/2 x Base x Height

Area of a trapezoid = 1/2 x (Base 1 + Base 2) x Height

Area of a circle = π x r

Lesson 19 Classwork

Example: Area of a Parallelogram

The coordinate plane below contains figure P, parallelogram ABCD.

a. Write the ordered pairs of each of the vertices next to the vertex points.

b. Draw a rectangle surrounding figure P that has vertex points of A and C. Label the two triangles in the figure as S and T.

c. Find the area of the rectangle.

d. Find the area of each triangle.

e. Use these areas to find the area of parallelogram ABCD.

The coordinate plane below contains figure R, a rectangle with the same base as the parallelogram above.

f. Draw triangles S and T next to R so that you have a rectangle that is the same size as the one you created on the first coordinate plane.

g. Find the area of rectangle R.

h. What do figures R and P have in common?

Exercises

1. Find the area of triangle ABC.

2. Find the area of quadrilateral ABCD two different ways.

3. The area of quadrilateral ABCD = 12 sq. units. Find x.

4. The area of triangle ABC = 14 sq. units. Find the length of side BC.

5. Find the area of triangle ABC.

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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