In mathematics, 'is' would be the equal sign. And 'of' would be the multiplcation sign. The missing number would be any variable.
56 is 28% of a number would be translated algebraically to:

Solving for x, we get:

Divide 28 on both sides

Multiply 100 on both sides
56 is 28% of 200
For #1 the answers are
69 degrees
155 degrees
86 degrees
335 degrees
249 degrees
Is there a picture to go with this problem?
You already know what it is cuh