Prove that the area of a circular path of uniform width h surrounding a circular region of radius r is πh(2r+h)

Matching exercise

    
Match the items on the right to the items on the left.
Step 1
Step 2
Step 3
Step 4
screenshot13.12_31_2.png
screenshot13.12_31_4.png
screenshot13.12_31_1.png
screenshot13.12_31_3.png