Calculating Area of Rectangles and Squares

The video tutorial for third graders covers Lesson 13, focusing on finding areas by decomposing rectangles and completing composite figures to form rectangles. It explains how to solve area problems by breaking larger rectangles into smaller ones and using two strategies for composite shapes: breaking them up into smaller rectangles or making them bigger and subtracting the extra area. The tutorial includes examples and encourages students to apply these strategies independently.

What is the main focus of Lesson 13?

• Understanding the properties of triangles

• Finding areas by decomposing rectangles

• Calculating the volume of cubes

• Finding the perimeter of circles

How can Anil find the area of a 5 inch by 17 inch rectangle?

• By subtracting the sides

• By breaking it into two smaller rectangles

• By dividing the rectangle into four parts

• By adding the sides together

What is the area of a rectangle that is 5 inches by 17 inches?

• 85 square inches

• 90 square inches

• 75 square inches

• 80 square inches

What is a composite shape?

• A shape with no sides

• A shape made of multiple simple shapes

• A shape that is not a rectangle

• A shape made of only circles

How can you find the area of an L-shaped figure?

• By adding the lengths of all sides

• By breaking it into a square and a rectangle

• By multiplying the perimeter by two

• By dividing it into four equal parts

What is the area of a 2 by 2 square?

• 4 square units

• 8 square units

• 6 square units

• 2 square units

How can you make a composite shape bigger to find its area?

• By dividing it into smaller parts

• By subtracting from its perimeter

• By pretending it is a larger rectangle or square

• By adding more sides

What is the area of a 4 by 4 square?

• 24 square units

• 20 square units

• 16 square units

• 12 square units

In the example of a non-rectangular shape, what is one way to find its area?

• By subtracting the area of a circle

• By adding the lengths of all sides

• By multiplying all sides together

• By breaking it into two rectangles

What is the area of a 2 by 5 rectangle?

• 5 square units

• 10 square units

• 15 square units

• 20 square units