Question

Calculate the area of triangle CDE with altitude EF, given C (3, −2), D (−1, 2), E (2, 3), and F (0, 1).

Answer 1

CD=√((-1-3)²+(2+2)²)=√(16+16)=√32=4√2
Altitude EF=√((0-2)²+(1-3)²)
=√(4+4)=√8=2√2
area=1/2 ×4√2×2√2=8 square units