/3/ - 3DCG

>>778786
You can just go into object mode, hit s, immediately click the left mouse button to not change anything and then you have a little window you can enter precise numbers in or even math operations.
Click and drag over all three parts so you edit x y and z at the same time and then write your target height divided by the current height, so for example 3 / 2.7 and hit enter, afterwards apply the scale.
There might be nicer ways to do this but it's the first that comes to mind.