The formula A=1/2bh is used to find the area of a triangle. You can find from the diagram that the base of this triangle is 9cm, and the height is 4cm. Plug those numbers into the area of a triangle formula.
Easiest question I have ever seen! :) We know the formula of the area of a triangle =×base×height The height given is 4 cm (we should take the perpendicular height) And the base length is 8 cm Simply, we just substitute the given numbers =×8×4 =18 cm² The answer is D: 18 square m
