Are the ratios 5:18 and 1:2 equivalent?

 No; they are not equivalent.

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Step-by-step explanation:

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Note: The ratio:  " 1:2 " ;  can be written as:  " " ;

         The ratio:  " 5:18 " ; can be written as: " " .

  → " " ;

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 → " " ;

                   → " " ;

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 → " " ;

                   → " " ;

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 → " " ;

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                   → " " ;

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 → " " ;

                   → " " .

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Hope this helps!

Best wishes!

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x = 25

step-by-step explanation:

a^2+b^2=c^2

7^2+24^2=c^2

49+576=625

sqrt625=25

x=25