The perimeter of a triangle is found the same way as the perimeter of a rectangle. It is the measure of the outside edges. In this course, we will give you the lengths of the sides of a triangle in order to find the perimeter. Finding the lengths of the sides is outside the scope of this course.

Here are some vocabulary to review for this lesson.

- Triangle = a 3 sided shape
- Equilateral Triangle = a triangle whose sides are all the same length
- Perimeter of a triangle = add all the lengths of the sides together.

Perimeter of a Triangle

### Practice Problems

- Find the perimeter of a triangle with sides a, b, and c, where a = 14, b = 20, and c = 8. (Solution
- Find the perimeter of a triangle with sides a, b, and c, where a=12.5, b=13.8, and c=16.3. Round your answer to the nearest tenth. (Solution
- Oliver is building a garden that is in the shape of a triangle with sides of length 9 m, 12 m, and 5 m. If Oliver wants to build a fence around the perimeter of his garden, how many meters of fencing does he need to buy? (Solution
- Gabriel rides his bike every morning and follows a path that forms a triangle with distances of 8.4km, 12.5km, and 9.2km. When Gabriel finishes his bike ride, how far has he ridden? Round to the nearest tenth. (Solution
- An equilateral triangle has sides of length 6 m. Find the perimeter of this equilateral triangle. (Solution
- A triangle has sides with lengths a, b, and c. The length of side a is 15 inches, and side b is two more inches than side a. If the perimeter of the triangle is equal to 40 inches, what is the length of side c? (Video Solution
- A triangular slice of pizza has a perimeter of 45 centimeters (cm). One side of the pizza slice is 18 cm with an adjacent side that is half the length of the first side. What is the length of the third side? (Video Solution

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