Which of the following sets of numbers could represent the three sides of a right triangle?
21, 72, 75,
7, 8, 10
8, 12, 15
14, 84, 85

21 , 72 , 75

Step-by-step explanation:

The one that could represent the three sides of a right angle triangle must obey Pythagoras theorem , that is

a=side of right triangle

b=side of right triangle

c=hypotenuse

Let's check the sides one after the other

1.

this means that

this could represent the three sides of a right triangle

2.

3.

4.

Therefore , the only combination that could represent the three sides of a right triangle will be 21 , 72 , 75

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,