Finding Perimeter and Missing Sides

In this video, Mr. Jay explains how to find the perimeter of a composite shape with missing side lengths. He begins by defining the perimeter as the distance around a shape and emphasizes the need to add all sides. The video demonstrates how to find missing side lengths using known measurements and then calculates the perimeter by adding all sides. The process is illustrated with an example, and Mr. Jay provides a step-by-step guide to ensure accuracy. The video concludes with a recap of the method and encourages viewers to start by finding unknown side lengths before calculating the perimeter.

What is the perimeter of a shape?

• The diagonal of the shape

• The volume of the shape

• The area inside the shape

• The distance around the shape

What is the first step in finding the perimeter of a composite shape with missing sides?

• Calculate the area

• Find the missing side lengths

• Measure the angles

• Draw the shape

Tags

CCSS.8.G.B.8

If a vertical side measures 11 feet and one part is 4 feet, what is the length of the missing part?

• 8 feet

• 5 feet

• 6 feet

• 7 feet

How do you determine the length of a missing horizontal side if you know two other horizontal sides are 8 feet and 6 feet?

• Subtract them

• Divide them

• Add them together

• Multiply them

Tags

CCSS.8.G.B.7

What is the length of the missing horizontal side if the known sides are 8 feet and 6 feet?

• 14 feet

• 15 feet

• 13 feet

• 12 feet

What is the next step after finding all missing side lengths?

• Draw the shape

• Measure the angles

• Add all the side lengths

• Calculate the area

Tags

CCSS.3.MD.D.8

What is the perimeter of the shape if the side lengths are 6, 11, 14, 4, 8, and 7 feet?

• 48 feet

• 50 feet

• 52 feet

• 45 feet

Why is it important to cross off sides as you add them?

• To calculate the area

• To ensure you don't miss any sides

• To measure the angles

• To make the shape look neat

What should you do if you have unknown side lengths in a composite shape?

• Guess their values

• Ignore them

• Estimate them

• Find them first

Tags

CCSS.3.MD.D.8

What is the final perimeter of the composite shape in the example?

• 50 feet

• 55 feet

• 45 feet

• 60 feet

Tags

CCSS.3.MD.D.8