Find the mean proportion between 21 and 189.

Given: 

two numbers;- 21, 189 

Formula Used: 

if a and b are two numbers, then 

Mean proportion = $$\sqrt{ab}$$ 

Solution: 

Mean proportion = $$\sqrt{21 \times 189}$$ 

                         = $$\sqrt{ 21 \times 21 \times 9}$$ 

                        = 63 

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