The graphic says find BC and it says BC = 33 feet
Anyway, assuming the ladder is 34 feet, and makes an 82 degree angle,
cosine 82 degrees = adjacent / hypotenuse
adjacent = cosine 82 degrees * hypotenuse
adjacent = 0.13917 * 34
adjacent (or side BC) = 4.73178 feet
height (line AB) = sine (82 degrees) * hypotenuse (34 feet)
height (line AB) = 0.99027 * 34
height (line AB) = 33.67 feet