Determine the value of X

72.9

Step-by-step explanation:

Fractions method:

because 90/100 is the same thing as 90%

That gives us 7290/100, from 81*90/100

Simplify: =729/10 = 72.9

Decimals method:

81*9 = 729, add in decimal and that's 72.9

Cross-multiplication:

90    100

?         81

This is read as 90 to 100, (as a ratio) so how many to 81? To solve, cross-multiply - 81*90=7290, then divide by 100 to get 72.9.

This is my first answer , hope it helped!