Find Unknown Side Lengths in Perimeter

Front

What is perimeter?

Back

Perimeter is the total distance around the outside of a shape.

Front

How do you find the perimeter of a rectangle?

Back

Add the lengths of all four sides or use the formula: P = 2(length + width).

Front

If a rectangle has a length of 10m and a width of 5m, what is its perimeter?

Back

P = 2(10m + 5m) = 30m.

Front

What is the formula to find the missing side length if you know the perimeter?

Back

If P is the perimeter and you know the lengths of the other sides, use: Missing side = P - (sum of known sides).

Front

Carlos has a garden that is 7 feet long and 6 feet wide. What is the perimeter?

Back

P = 2(7ft + 6ft) = 26ft.

Front

If one side of a square is 4 inches, what is the perimeter?

Back

P = 4 sides x 4 inches = 16 inches.

Front

What is the missing side length if the perimeter is 50m and the other sides are 15m and 10m?

Back

Missing side = 50m - (15m + 10m) = 25m.

Front

How many feet of fencing does Carlos need for a rectangular garden that is 5 feet long and 3 feet wide?

Back

P = 2(5ft + 3ft) = 16ft.

Front

What is the perimeter of a triangle with sides measuring 3cm, 4cm, and 5cm?

Back

P = 3cm + 4cm + 5cm = 12cm.

Front

If a rectangle has a perimeter of 40m and one side is 10m, what is the other side?

Back

Other side = (40m - 10m) / 2 = 15m.