Trig

if 16+25+-2(20)CosC=36 , what is the angle measure of C ?
Before you even start you need to make sure you calculator is in degrees or radians - whichever one you need

Why are you confused ?

It would be more helpful if you put the brackets like this, you will be less likely to make mistakes.

16+25 - (2*20*CosC)=36

Once you solve for CosC then put the answer in you calc and press inv cos to get the value of C

Is that enough help?

what confuzes me is that when i solve for C , I end up with 47.55 which makes no sense considering angle C is the largest angle in the triangle

16+25 - (2*20*CosC)=36

42- (40cosC) = 36

6 = 40cosC

6/40 = cosC

cosC = 0.15

inverse cos 0.15 = 81.37 degrees

It is really good that you recognised that you needed an angle bigger than 60degrees.
Can you work out what you have been doing wrong?