7.5+k=10 7.5+k-7.5=10-7.5 step 1 k=2.5 step 2 find her mistake
a: step 1
b: step 2
c: no mistake

The trapezoid is composed of a rectangle and two triangles. what is the area of the rectangle? what is the total area of the triangles? what is the area of the trapezoid? a) 48 cm2; 32 cm2; 80 cm 2 b) 48 cm2; 16 cm2; 64 cm 2 c) 128 cm2; 32 cm2; 160 cm 2 d) 128 cm2; 16 cm2; 144 cm 2