Question

Many television screens are rectangles that are measured by the length of their diagonals. The ratio of the horizontal length to the height in a standard television screen is $4 : 3.$ The horizontal length of a "27-inch" television screen is closest, in inches, to which of the following?

$20$

$20.5$

$21$

$21.5$

$22$

Answer: D

Concepts:Pythagorean Triple ratio and proportion

Difficulty rating: 1000

Solution:

Since the length and height are in ratio $4:3,$ the length, height, and diagonal form a $4:3:5$ right triangle. The diagonal is $27,$ so the horizontal length is $\dfrac{4}{5}(27)=21.6,$ which is closest to $21.5.$

Thus, the correct answer is D.

2003 AMC 10B Problem 6

Answer: D

Difficulty rating: 1000

Solution:

Problem 6 in Other Years