Point A in the x*y-coordinate system is shown below. Given two other points B (4a, b) and C (2a, 5b), what is the area of triangle ABC in terms of a and b?
A.7·a·b2
B.9·a·b2
C.15·a·b2
D.4*a*b
E.6*a*b
我的答案：
Point A in the x*y-coordinate system is shown below. Given two other points B (4a, b) and C (2a, 5b), what is the area of triangle ABC in terms of a and b?
