Changing the size of what you want to cut

How do you manually change the size of what you would like to cutout. Stupid question I know, trying to learn this the best that I can.

In Fusion 360, measure whatever part you want to specify the final size. Divide the size you want it to be by the size it actually is drawn and that number is your scale ratio. So if it’s 3" in your drawing and you need it 4.5" your scale factor is 1.5 Select the whole part and scale it. >1 makes it bigger and a decimal less than 1 makes it smaller.