To find the measures of the angles, we need to use the fact that complementary angles add up to 90 degrees.

Given angles are $(7f)^\circ$ and $(2f)^\circ$.

The equation for complementary angles is: $7f + 2f = 90^\circ$

Solving for $f$: $9f = 90$ $f = \frac{90}{9}$ $f = 10$

Now, substitute $f$ back into the expressions for the angles: $7f = 7 \times 10 = 70^\circ$ $2f = 2 \times 10 = 20^\circ$

So, the measures of the angles are $70^\circ$ and $20^\circ$.

The correct answer is:

C. 70 and 20

Would you like further details or have any questions about this solution?

Here are some questions you can ask:

1. Can you explain the concept of complementary angles in more detail?
2. How can I determine if two angles are complementary without solving an equation?
3. What are supplementary angles and how do they differ from complementary angles?
4. How can I solve similar angle problems involving more complex equations?
5. Can you provide another example of finding complementary angles with different expressions?

Tip: Remember that complementary angles always sum up to 90 degrees, while supplementary angles sum up to 180 degrees.