The Total solution for NCERT class 6-12
Radius of inner circle = rWidth of path = h∴ Outerradius (R) = (r + h)∴ Areaof path = πR2 – πr2= π {(r + h)2 – r2}= π {r2 + h2 +2rh – r2}= π {2rh + h2}= πh (2r + h) Hence proved.