Question: How do we calculate the are of rectangles and triangles?

Answer: First of all what is area?
The area of a figure is the measure region enclosed by the figure.

Okay now that we know what area is, lets find out how to find the area of a rectangle! :D
The area of a rectangle can be found by multiplying the length(L) times the width(W). AREA=L*W

Figure 1

The area is measured in "units squared." If your rectangle is 5 inches long and 3 inches wide, to find the area you must multiply these two. so it would be: 5inches * 3 inches = 15inches(squared). Illustrated in Figure 1.

 Now lets find out how to find the area of a triangle. To find the area of a triangle you do one half the base times the height. AREA=(1/2)B*H

NOW YOU TRY! :D

Find the area of the rectangle above.