Question

a ladder is placed aganist the wall of a building 20m above the ground .The foot of the ladder is 15m away from the bottom of the building.W
hat is the length of the ladder

Answer 1

Let
AB be foot of ladder=15m
AC be height from ground=20m

Now Angle BAC is 90 ° as ground is perpendicular to wall

Hence by Pythagoras theorem
${AB}^{2} + {AC}^{2} = {BC}^{2} \\ {BC}^{2} = {15}^{2} + {20}^{2} \\ {BC}^{2} = 225 + 400 \\ BC = \sqrt{625} \\ BC= 25m$
Length of Ladder is 25 m

Answer 2

d the length of the ladder is 25 m because the angle made at the bottom of the building is of 90° b y Pythagoras theorem we can see that length of ladder square is equal to square of building height + square the distance between ladder and building foot is 25m