SAT Math · Linear equations in one variable · medium
A regular pentagon has a side length of 3x - 2. If the perimeter of the pentagon is 80, what is the value of x?
A regular pentagon has a side length of . If the perimeter of the pentagon is 80, what is the value of ?
Answer and explanation
Answer: B: 6
A regular pentagon has 5 equal sides, so the perimeter is . Divide by 5: . Add 2: , so , choice B. Check: the side is 16, and . Choice A (28) gives a side of 82 and a perimeter of 410. Choice C (5) is the number of sides. Choice D (7) gives a side of 19 and a perimeter of 95. Use the number of sides that the shape actually has: 5 for a pentagon.
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