If the side opposite a 60-degree angle in a 30-60-90 right triangle is 

7
3


 cm
 long, how long is the hypotenuse?(1 point)

In a 30-60-90 right triangle, the ratio of the side opposite the 30-degree angle to the hypotenuse is 1:2, and the ratio of the side opposite the 60-degree angle to the hypotenuse is √3:2.

Given that the side opposite the 60-degree angle is –√7 cm long, we can set up the following equation:

√3/hypotenuse = –√7/2

To solve for the hypotenuse, we can cross-multiply:

hypotenuse*√3 = 2*(-√7)

hypotenuse = (2*(-√7))/√3

hypotenuse = -2(√7/√3)

Since we can't have a negative length, we discard the negative sign:

hypotenuse = 2(√7/√3)

Simplifying further:

hypotenuse = 2(√21/√9)

Since √9 = 3, we can simplify again:

hypotenuse = 2(√21/3)

Therefore, the length of the hypotenuse is 2(√21/3) cm.