Question

The shorter leg of a right triangle is 21 feet less than the other leg. Find the length of the two legs if the hypotenuse is 39 feet.

Answer 1

Answer:

leg 1= 36  feet

leg2 = 15  feet

Step-by-step explanation:

Hi, we have to apply the Pythagorean Theorem:  

c^2 = a^2 + b^2  

Where c is the hypotenuse of the triangle (in this case the distance between Doreen’s house and the tower) and a and b are the other legs.  

leg1 = x

leg2 = x-21 (21 feet less than the other leg)

Replacing with the values given:  

39^2 = x^2 + (x-21)^2  

1,521 = x^2 + x^2 -42x +441

0 = 2x^2 -42x +441-1,521

0= 2x^2 -42x -1,080

For: ax2+ bx + c  

x =[ -b ± √b²-4ac] /2a  (quadratic formula)

Replacing with the values given:  

x=-(-42)± √(-42)²-4(2)-1080] /2(2)  

x= 42± √10,404] /4

x = 42± 102 /4

Positive:

x = 42+102 /4 = 36

leg 1= 36

leg2 = 36-21 =15

Feel free to ask for more if needed or if you did not understand something.