Collection of eight geometry problems where students must calculate the complementary angle based on the provided diagrams.

Problem: Identify the angle of the complementary angle.

#### Definition of Complementary Angles:
Two angles are complementary if the sum of their measures is 90°. If one angle is \( x \), then its complementary angle is \( 90^\circ - x \).

#### Solution:

We will solve each part step by step:

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Part 1:

- Given angle: \( 36^\circ \)
- Complementary angle: \( 90^\circ - 36^\circ = 54^\circ \)

Answer for Part 1: \( \boxed{54^\circ} \)

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Part 2:

- Given angle: \( 40^\circ \)
- Complementary angle: \( 90^\circ - 40^\circ = 50^\circ \)

Answer for Part 2: \( \boxed{50^\circ} \)

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Part 3:

- Given angle: \( 25^\circ \)
- Complementary angle: \( 90^\circ - 25^\circ = 65^\circ \)

Answer for Part 3: \( \boxed{65^\circ} \)

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Part 4:

- Given angle: \( 70^\circ \)
- Complementary angle: \( 90^\circ - 70^\circ = 20^\circ \)

Answer for Part 4: \( \boxed{20^\circ} \)

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Part 5:

- Given angle: \( 75^\circ \)
- Complementary angle: \( 90^\circ - 75^\circ = 15^\circ \)

Answer for Part 5: \( \boxed{15^\circ} \)

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Part 6:

- Given angle: \( 85^\circ \)
- Complementary angle: \( 90^\circ - 85^\circ = 5^\circ \)

Answer for Part 6: \( \boxed{5^\circ} \)

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Part 7:

- Given angle: \( 20^\circ \)
- Complementary angle: \( 90^\circ - 20^\circ = 70^\circ \)

Answer for Part 7: \( \boxed{70^\circ} \)

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Part 8:

- Given angle: \( 50^\circ \)
- Complementary angle: \( 90^\circ - 50^\circ = 40^\circ \)

Answer for Part 8: \( \boxed{40^\circ} \)

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Final Answers:

1. \( \boxed{54^\circ} \)
2. \( \boxed{50^\circ} \)
3. \( \boxed{65^\circ} \)
4. \( \boxed{20^\circ} \)
5. \( \boxed{15^\circ} \)
6. \( \boxed{5^\circ} \)
7. \( \boxed{70^\circ} \)
8. \( \boxed{40^\circ} \)