Question

6
A rectangular plywood measures 2.1 m by 70 cm. Circular discs are to be cut out
from the plywood of diameter 14 cm. How many discs can be cut and how much
plywood will be left?​

Answer 1

Answer:

discs can be cut = 95

leftover plywood = 70 cm^2

Step-by-step explanation:

area of rectangle = l x b

                          l  = 2.1 m x 10= 210 cm

                         b  = 70 cm

                             = 210 x 70

                             = 14700 cm^2

                           

area of circular disc = $\pi$r^2

                                 = 22/7 x 7 x 7 ( r=d/2=14/2 = 7cm)

                                 = 22 x 7

                                 = 154cm^2

no. of discs = ar. of rectangle/ ar. of circle

                   = 14700/ 154

                   = 95

therefore, 95 discs can be cut

area of 95 discs = 154 x 95 = 14630 cm^2

area of leftover plywood = 14700 - 14630 = 70 cm^2

therefore, 70 cm^2 of plywood will be left.