You can multiply the whole number by the denominator. 10x5 is 50. Then add the numerator to the number. 50+2 is 52. Put the new number over the original denominator to complete the process. 52/5.
The equation for this is a^2+b^2=c^2 so your equation would be 7^2+20^2=X So you square the 7 and the 20 then take the square root of X and you get X=21.19 :)
