Area of one small semicircle =π2×(1510)2
Area of the given figure =π2[45×45100+15×15100]=45π4cm2
Area of circle =π×(4510)2
Area of the shaded region = Area of a given figure - Area of circle −2× Area of small semicircles
=45π4−45×45π100×4−2×π2(15×15100)
=45π100×[25−11.25−5]
=45×22100×7×8.75
Area of the shaded region=12.375cm2