2

Set 3: Triangles

Explanation

Answer: B

A triangular picture frame has sides measuring 7 kilometers and 17 kilometers. If the total perimeter is 39 kilometers, find the length of the third side.

A.

7

B.

15

✓ Correct
C.

5

D.

25

Detailed Explanation

Choice B is correct. The perimeter of a triangle is the sum of all three sides. 1. Total perimeter: 39 kilometers Two known sides: 7 + 17 = 24 kilometers Third side: 39 - 24 = 15 kilometers Therefore, the third side is 15 kilometers.

Key Steps:

The correct answer is 15

Why others are wrong:
A: This would give an incorrect result. Choice A is incorrect and may result from a calculation error.
C: This would give an incorrect result. Choice C is incorrect and may result from a calculation error.
D: This would give an incorrect result. Choice D is incorrect and may result from a calculation error.

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