Find area on triangle:
A=(1/2)bh
A=(1/2)(8 units) (6 units)
A=(1/2)(48 units^2)
A=24 units^2
Just do the same for the rest of this page following the equation for the area of a triangle A=(1/2) (base) (height)
Find the error:
A=(1/2)bh
100m^2=(1/2)b(20m)
100m^2=(10m)b
10m=b
He forgot to multiply bh by 1/2
Area of parallelogram:
A=bh
A=(3 units) (3 units)
A= 9 units^2
The red line is the height and the bottom of the parallelogram is the base, just count the squares. Imagine cutting the parallelogram at the red line and moving that triangle piece to the other side, it'll make a rectangle, that's why the equation is the same.