See the solutions to these problems just after the percentage calculator below.

Here are the solutions to the questions stated above:

Always use this formula to find a percentage:

^{%} / _{100} = ^{Part} / _{Whole} replace the given values:

^{3.1} / _{100} = ^{Part} / _{90}

Cross multiply:

3.1 x 90 = 100 x Part, or

279 = 100 x Part

Now, divide by 100 and get the answer:

Part = ^{279} / _{100} = 2.79

Use again the same percentage formula:

^{%} / _{100} = ^{Part} / _{Whole} replace the given values:

^{%} / _{100} = ^{3.1} / _{90}

Cross multiply:

% x 90 = 3.1 x 100

Divide by 90 and get the percentage:

% = ^{3.1 x 100} / _{90} = 3.4444444444444%