Krishna
0

Step 1: Understand the question and figure  

            NOTE: Each semi circle has drawn with side of square as a  diameter


Step 2: Name the un-shaded regions of the figure

          

          Let Unshaded regions be 1, 2, 3 and 4 

Step 3: Find the radius of the semicircle

            NOTE: Diameter = 10

                        Radius = \frac{10}{2} = 5

Step 4: Evaluate the area of the square  

          EXAMPLE: Area of square =   side^2

                                                      = 10^2

                                                      = 100

Step 5: Calculate the area of the semi-circle

            NOTE: Area of the semicircle = \frac{1}{2} \pi r^2

            EXAMPLE:  =   \frac{1}{2} * 3.14 * 5 * 5

                                = \frac{1}{2} * 3.14 * 25


Step 6: Find the areas of the un-shaded regions

          NOTE: Area of 1 + Area of 3= Area of ABCD – Areas of two semicircles of each of radius 5 cm 


             = (100 - 3.14 * 25)

             = (100 - 78.5)

             =21.5 cm²

           So,

           Even the Area of 2 and 4 is equal to 21.5 cm²


Step 7: Determine the area of the shaded region

          NOTE: Area of the shaded region = Area of ABCD - Area 0f ( 1+2+3+4)

           EXAMPLE: Area of the shaded region = 100 - (21.5 + 21.5)

                                                                         = 100 - 43

                                                                        =57 cm^2