Finding Perimeter and Side Lengths

In this video, Mr. J explains how to find an unknown side length of various shapes given their perimeter. The video covers examples with triangles, trapezoids, pentagons, and quadrilaterals, demonstrating how to set up equations to solve for the missing side. Practice problems are provided for viewers to try on their own, with solutions reviewed at the end. The lesson emphasizes the importance of including all side lengths in calculations and verifies solutions by checking the original perimeter equation.

What is the perimeter of a shape?

• The volume of the shape

• The distance around the outside of the shape

• The area inside the shape

• The number of sides of the shape

How do you find the perimeter of a shape?

• By subtracting the smallest side from the largest

• By dividing the total area by the number of sides

• By adding all side lengths

• By multiplying all side lengths

In a triangle with a perimeter of 12T and side lengths of 5T and 3T, what is the missing side length?

• 8T

• 6T

• 4T

• 2T

What is the first step in finding a missing side length when given the perimeter?

• Add the known side lengths

• Divide the perimeter by the number of sides

• Subtract the known side lengths from the perimeter

• Multiply the known side lengths

In a trapezoid with a perimeter of 38M and side lengths of 10M, 12M, and 10M, what is the missing side length?

• 6M

• 4M

• 8M

• 10M

What is a trapezoid?

• A shape with four sides, one pair of which is parallel

• A shape with three sides

• A shape with five sides

• A shape with all sides equal

In a pentagon with a perimeter of 34 inches and side lengths of 5 in, 7 in, 7 in, and 5 in, what is the missing side length?

• 10 in

• 9 in

• 8 in

• 11 in

What is the sum of the known side lengths in the pentagon problem?

• 34 in

• 29 in

• 24 in

• 19 in

In a quadrilateral with a perimeter of 49 CM and side lengths of 21 cm, 9 cm, and 12 cm, what is the missing side length?

• 5 cm

• 6 cm

• 7 cm

• 8 cm

What is the sum of the known side lengths in the quadrilateral problem?

• 49 cm

• 51 cm

• 42 cm

• 30 cm