A ladder of length 4.5m is leaning against a wall. The foot of the ladder is 2.3m from the base of the wall. What is the angle the ladder makes with the wall?

This is an application of trigonometry. The right angle in this case is between the wall and the floor and the hypotenuse is the ladder. The angle between the wall and the ladder can using the sine of the angle.
sin(angle) = opposite / hypotenuse = 3.2 /6.4 = 0.5Therefore, angle = sin^-1(0.5) = 30°
We can also use the cosine of the angle, although this would require an extra step of finding the length of the wall using Pythagoras.