Question

a 10 m long ladder is placed against a wall of a building . the foot of the ladder is 6 m away from the bottom of the building . how high against the wall does the ladder reach ?

Answer 1

the given arrangement forms a right angled triangle
whose base = 6m
height = 10m
length of height of ladder against the wall is the hypotenuse
using Pythagoras theorem
sum of length of two sides of a right angled triangle is always shorter than the third side
(base) ² + (height)² = (hypotenuse)²
(6)²+(10)² =( height of ladder against the wall )²
√136 = height of ladder against the wall => 11.66 m
hope this helps

Answer 2

it forms a right angled triangle whose base is 6 m and hypotenuse is 10 m 
we know that 
(hypotenuse)² = (base)² + (height)²
⇒(height)² = (hypotenuse)² -  (base)²
(high against the wall does the ladder reach )² = (10 m)² - (6 m)²
(high against the wall does the ladder reach )² = 100 m² - 36 m²
                                                                               = 64 m²
high against the wall does the ladder reach  = √64 m²
                                                                            = 8 m
answer = 8m 
hope it helps 
please mark brainliest