Question

What is the length of the diagonal of the rectangle? Round to two decimal places

A. 7.61
B. 16.31
C. 19.86
D. 38.60

Answer 1

Option C

Explanation:

By the property of a rectangle,

"All interior angles of a rectangle measure 90°"

Therefore, m∠ABC = 90°

By applying cosine rule in the right triangle ABC,

cos(∠CAB) =
`\frac{\text{Adjacent side}}{\text{Hypotenuse}}`

cos(25°) =
`(AB)/(AC)`

AC =
`\frac{AB}{\text{cos}(25)}`

AC =
`\frac{18}{\text{cos}(25)}`

AC = 19.86

Therefore, Option C will be the answer.