How to solve it don't understand a thing

1) 40ft^2

2)320mm^2

3) 96m^2

Step-by-step explanation:

first one

find the area of the bigger rectangle (80)

find the area of the inner rectangle (40)

subtract the bigger one from the smaller one(80-40=40)

shaded area is 40ft^2

second one

find the area as if it were a rectangle(720 cm)

find the area of the inner(400cm)

subtract the bigger from the smaller(720-400=320)

320mm^2

third

find area of the big square(196)

find area of one tiny unshaded square(25)

since all are the same 25x4 is 100

196-100=96

answer;96m^2

21.4 i did it already for s1

step-by-step explanation: