It is easy to calculate an isosceles triangle's perimeter because it is a simple shape. A triangle, also known as a trigon, is a polygon with three interior angles and three sides. Triangles are classified into different types by their angle and side length measurements. Isosceles triangles possess at least two congruent sides, which means that they are equal in size. The perimeter of any polygon or other closed, two-dimensional shape is the measurement of its border or exterior. You can find an isosceles triangle's perimeter with the measurements of one of its congruent sides and its incongruent side.
Instructions
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1
Measure the length of one of the congruent sides. For this example, one congruent side measures 8 inches.
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2
Multiply the length of the congruent side by 2. In this example, 8 x 2 = 16 inches.
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3
Measure the unknown third or base of the triangle. In this example, the base side is 6 inches.
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Add the base side's length to the doubled length of a congruent side to calculate the triangle's perimeter. Concluding this example, 16 + 6 = 22 inches.