The inner and outer diameters of ring 1 of a dartboard are 32cm and 34cm respectively and those of rings II are 19cm and 21cm respectively. What is the total area of these two rings?

Explanation

Given: For Ring I, `r_1​=16 and r_2​=17`

For Ring II, `r_1​=9.5 and r_2​=10.5`

Area of ring I = `(pi×17^2−pi×16^2)cm^2`

`=22/7​×(17^2−16^2)cm^2`

`=22/7​×(17+16)(17−16)cm^2`

`=22/7​×33 cm^2`

Area of ring II `=(pi×10.5^2−pi×9.5^2)cm^2`

`=pi(10.5^2−9.5^2)cm^2`

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