If the length of the longest side of a right triangle is 10 inches and one of the angles is 60 degrees, what is the length in inches of the shortest side

Тhe longest side of the right triangle is the hypotenuse.
The third angle of this triangle is 90 - 60 = 30°
The short leg is the side opposite the 30 degree angle.
In a 30-60-90  triangle the side opposite the 30 degree angle is half the length of the hypotenuse. 
If the the hypotenuse = 10 inches then the short leg = 10/2 = 5 inches 

The answe may be c