The DF side of the DFE triangle is 8cm. This is twice the length of the FE side.
| August 3, 2021 | education
The DF side of the DFE triangle is 8cm. This is twice the length of the FE side. Find the length of the side DE of the triangle DFE if its perimeter is 21 cm.
You are given a triangle DFE, and its perimeter is 21 cm.
The length of one side DF is known, it is 8 cm.
The DF side is twice as large as the FE side by the statement of the problem. Therefore, the length of the second side is equal to half the length of DF:
8/2 = 4 cm FE side length.
Given the values of the lengths of the two sides and the perimeter of the triangle, we calculate the length of the third sought-for side DE. To do this, subtract the sum of the lengths of the two known sides from the perimeter.
21 – (8 + 4) = 21 – 12 = 9 cm.
Answer: The length of the DE side is 9 centimeters.
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