The area of the composite figure is equal to the area of a triangle plus the area of a rectangle
so
step 1
Find out the area of the rectangle
A=(20)*(12)
A=240 in2
step 2
Find out the area of the triangle
A=(1/2)(20)*(10)
A=100 in2
therefore
the area of the figure is
A=240+100
A=340 in2
option C