Digital PSAT Math Practice Question 144: Answer and Explanation

Question: 144

A rectangle has side lengths of 6 inches and 8 inches. What is the length of the diagonal of the rectangle?

• A. 9 inches
• B. 10 inches
• C. 12 inches
• D. 13 inches

Correct Answer: B

Explanation:

(B) You can use the Pythagorean theorem to calculate the length of the diagonal of this rectangle since you know the two side lengths of 6 and 8:

Alternatively, you could recognize that 6-8-10 is a multiple of the Pythagorean triple 3-4-5, thus saving you the trouble of calculating using the Pythagorean theorem.