10
Answer: DSet 3: Triangles
Explanation
Sofia wants to build a triangular fence for a airport. Two sides measure 7 feet and 10 feet. If Sofia has exactly 21 feet of fencing material, what must be the length of the third side?
A.
14
B.
2
C.
8
D.✓ Correct
4
Detailed Explanation
Choice D is correct. The perimeter of a triangle is the sum of all three sides. 1. Total perimeter: 21 feet Two known sides: 7 + 10 = 17 feet Third side: 21 - 17 = 4 feet Therefore, the third side is 4 feet.
Key Steps:
•
The correct answer is 4
Why others are wrong:
A: This would give an incorrect result. Choice A is incorrect and may result from a calculation error.
B: This would give an incorrect result. Choice B 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.
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