What is the result by dividing each term of the identity sin

What is the result by dividing each term of the identity: sin^2 (x) + cos^2 = 1 by cos^2 (x) In a right triangle, the side opposite the 45 degree angle is 1058 ft long, find the length of the adjacent side.

sin^2x+cos^2x=1 can be divided by cos^2x like below

sin^2x/cos^2x+cos^2x/cos^2x=1/cos^2x