sat suite question viewer

Geometry and Trigonometry Difficulty: Easy
  Perimeter
Triangle TUV 50
Triangle XYZ 150

The table gives the perimeters of similar triangles TUVTUV and XYZXYZ, where TU corresponds to XY. The length of TU is 6 .

What is the length of XY?

Back question 237 of 268 Next

Explanation

Choice C is correct. It’s given that triangle TUV is similar to triangle XYZ, and TU¯ corresponds to XY¯. If two triangles are similar, then the ratio of their perimeters is equal to the ratio of their corresponding sides. It’s given that the perimeter of triangle TUV is 50, the perimeter of triangle XYZ is 150, and the length of TU¯ is 6. Let n represent the length of XY¯. It follows that 50150=6n, or 13=6n. Multiplying each side of this equation by n yields n3=6. Multiplying each side of this equation by 3 yields n=18. Therefore, the length of XY¯ is 18.

Choice A is incorrect. This is the solution to 31=6n, not 13=6n.

Choice B is incorrect. This is the length of TU¯, not XY¯.

Choice D is incorrect. This is the sum of the length of TU¯ and the perimeter of triangle TUV, not the length of XY¯.