Question 23

$$ If  3\sqrt{5} + \sqrt{125} = 17.88, then  find  the  value  of  \sqrt{80} + 6\sqrt{5} $$

Solution

$$3\sqrt{5} + \sqrt{125} = 17.88$$

$$3\sqrt{5} + \sqrt{25\times 5} = 17.88 $$

$$3\sqrt{5} + \5sqrt{5} = 17.88 $$

$$8\sqrt{5} = 17.88 $$

then,

 $$\sqrt{80} + 6\sqrt{5} $$ =  $$\sqrt{16\times5} + 6\sqrt{5} $$

                                        =  $$4\sqrt{5} + 6\sqrt{5} $$

                                          = $$10\sqrt{5}$$

  if $$8\sqrt{5} = 17.88 $$, then 

   $$10\sqrt{5}$$ = 22.35


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