Me out if u get answer right u wil get branliest

1. find the area of the unshaded square 2. find the area of the large square 3. what is the area of the frame represented by the shaded region show

Emily is entering a bicycle race for charity. her mother pledges $0.90 for every 0.75 mile she bikes. if emily bikes 18 miles, how much will her mother donate?

20 ! brainliest ! add and simplify your answer.