The circumference of a circle is equal to the sum of the circumference of two circles having diameters 36 cm and 20 cm. The radius of the new circle is

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28 cm Let r cm be the radius of the new circle. We know: Circumference of the new circle = Circumference of the circle with diameter 36 cm + Circumference of the circle with diameter 20 cm Thus, we have: 2$\pi$r = 2$\pi$r + 2$\pi$r2 $\Rightarrow$ 2$\pi$r = (2$\pi$ $\times$ 18) + (2$\pi$ $\times$ 10) $\Rightarrow$ 2$\pi$r = 2$\pi$ $\times$ (18 + 10) $\Rightarrow$ 2$\pi$r = (2$\pi$r $\times$ 28 ) $\Rightarrow$ 2$\pi$r =( 2 $\times$ $\frac{22}{7}$xx28) $\Rightarrow$ 2$\pi$r = 176 $\Rightarrow$ 2 $\times$ $\frac{22}{7}$xx"r"=176 => "r" = (176xx7/44) $\Rightarrow$ r =28 cm

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