# Section B: Practice Problems Reason about Attributes to Solve Problems

## Section Summary

Details

In this section, we used the attributes such as side lengths, angles, lines of symmetry, and parallel sides to solve problems about perimeter of shapes.

We learned that, if a shape has certain attributes, we can use them to find its perimeter, even if we don’t have all of its side lengths. Or, if we know the perimeter of a shape, we can find its side lengths if there is enough information about their attributes.

For example, here are two shapes:

If we know the perimeter of each shape is 48 units and the dashed line through shape A is a line of symmetry, we can find the missing side lengths.

Shape B doesn’t have a line of symmetry, but if we were told that its opposite sides have equal lengths, then we can also reason about the three missing side lengths.

## Problem 1 (Lesson 7)

1. What is the perimeter of the rhombus? Explain or show your reasoning.

2. Diego says he can find the area of this rectangle because he knows two side lengths.

Do you agree with Diego? Explain your reasoning.

## Problem 2 (Lesson 8)

1. Draw the lines of symmetry for the windmill blades.

2. Each blade is 5 feet long and feet wide. What is the perimeter of the windmill? Explain or show your reasoning.

## Problem 3 (Lesson 9)

Here is a rectangle R.

1. What shape can be folded along a line of symmetry to give R? What are the side lengths of that shape?