Answer :
Given:
The base of 40-foot ladder is 8 feet from the wall.
To find:
How high is the ladder on the wall (round to the nearest foot).
Solution:
Ladder makes a right angle triangle with wall and ground.
We have,
Length of ladder (hypotenuse)= 40 foot
Base = 8 foot
We need to find the perpendicular to get the height of the ladder on the wall.
Let h be the height of the ladder on the wall.
According to the Pythagoras theorem,
[tex]Hypotenuse^2=Base^2+Perpendicular^2[/tex]
[tex](40)^2=(8)^2+(h)^2[/tex]
[tex]1600=64+h^2[/tex]
[tex]1600-64=h^2[/tex]
[tex]1536=h^2[/tex]
Taking square root on both sides.
[tex]\pm \sqrt{1536}=h[/tex]
[tex]\pm 39.1918358=h[/tex]
Height cannot be negative. Round to the nearest foot.
[tex]h\approx 39[/tex]
Therefore, the height of the ladder on the wall is 39 foot.