Find the area of △DEF with vertices D(5, 16), E(12, 6), and F(4, 6). The area of △DEF is square units.

Answer 1

The area of a triangle = 1/2 * length of base * height

If you plot the points in the x-y coordinate graph and connect the points to form a triangle,

you will see that the base is formed by the straight line between (4,6) and (12,6) which is of length 12-4 = 8.

if you draw a straight line (known as an altitude) from point (5,16) to the base you will see that the length is 16 -6 = 10. That length is the height.

So the area is thus 1/2 * 8 * 10 = 40 square units