Answer:
C) 19.5 square units
Step-by-step explanation:
The area from coordinates can be computed as ...
A = (1/2)|x1(y2 -y3) +x2(y3 -y1) +x3(y1 -y2)|
= (1/2)|7(10 -4) +0(4 -1) +9(1-10)| = (1/2)|7·6 +9·(-9)|
= (1/2)|-39| = 39/2 = 19.5
The area of the triangle is 19.5 square units.
