Question

Let $PQRS$ be a square piece of paper. $P$ is folded onto $R$ and then $Q$ is folded onto $S.$ The area of the resulting figure is 9 square inches. Find the perimeter of square $PQRS.$

$9$

$16$

$18$

$24$

$36$

Answer: D

Concepts:paper folding area

Difficulty rating: 1360

Solution:

After the two folds, the resulting triangle has area $9$ . Four congruent copies of this triangle make the original square.

So the square has area $4\cdot9=36$ , giving side length $6$ . Its perimeter is $4\cdot6=24$ .

Thus, the correct answer is D .

1998 AMC 8 Problem 20

Answer: D

Difficulty rating: 1360

Solution:

Problem 20 in Other Years