Calculate the area of triangle abc with altitude cd, given a(6,-2), b (1,3), c (5,5), and d (2,2) a. 12 square units b. 13 square units c. 14 square units d. 15 square units

You know the formula of distance between 2 points A(a;b) and B(x;y)
AB=
So we can calculate: CD=√(2-5)²+(2-5)² =√18 =3√2
and AB=√(6-1)²+(-2-3)² = √50= 5√2

and the area S=1/2*AB*CD= 1/2 * 3√2 *5√2 =15
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The answer is (a) 12-2(-1)(6)2(6)=12