Whoa! You made a rectangle that's twice as big as the triangle! The area of the rectangle is
b
h
=
4
×
5
=
20
bh=4×5=20b, h, equals, 4, times, 5, equals, 20 square units, so the area of the triangle is
1
2
b
h
=
1
2
×
4
×
5
=
10
2
1
bh=
2
1
×4×5=10start fraction, 1, divided by, 2, end fraction, b, h, equals, start fraction, 1, divided by, 2, end fraction, times, 4, times, 5, equals, 10 square units.