Answer:
b. 15 square units
Step-by-step explanation:
We notice from the graph that AB is the hypotenuse of a right triangle 3 units wide and 6 units high. The Pythagorean theorem tells you the length of that will be ...
AB = √(3^2 +6^2) = √45 = 3√5
Similarly, altitude CD is the hypotenuse of a right triangle 4 units wide and 2 units high, so its length will be ...
CD = √(4^2 +2^2) = √20 = 2√5
The area is given by the formula ...
A = 1/2bh
A = 1/2(3√5)(2√5) = 15 . . . square units