# Perpendicular Lines

Videos to help Grade 4 students learn how to identify, define, and draw perpendicular lines.

Common Core Standards: 4.G.1

## New York State Common Core Math Module 4, Grade 4, Lesson 3

NYS Math Module 4 Grade 4 Lesson 3 Application Problem

1. Use a straight edge to draw and label line segment AB, CD, and EF as modeled on the board.

2. Estimate to draw point X halfway up line segment AB.

3. Estimate point Y halfway up line segment CD.

4. Draw horizontal line segment XY. What word did you write?

5. Erase segment XY. Draw segment CF. What word did you draw?

Lesson 3 Concept Development

Problem 1: Define perpendicular lines. Perpendicular lines are lines that intersect at right angles.
Problem 2: Identify perpendicular lines by measuring right angles with a right angle template.
Problem 3: Recognize and write symbols for perpendicular segments.

Lesson 3 Homework

1. On each object, trace at least one pair of lines that appear to be perpendicular.
3. In the square and triangular grids below, use the given segments in each grid to draw a line that is perpendicular using a straightedge.

Lesson 3 Problem Set

4. Use the right angle template that you created in class to determine which of the following have a right angle. Mark each right angle with a small square. For each right angle you find, name the corresponding pair of perpendicular lines. (See 4(a) for one example of this.)