To solve the given problems, let's analyze the information and the diagrams step by step.

Problem Analysis

Diagrams and Given Information

1. 图1 and 图2:

   • $AB \parallel CD$
   • Points $E$ and $F$ are on $AB$ and $CD$ respectively.
   • Point $G$ is between $AB$ and $CD$.
   • $\angle BEG = 40^\circ$
   • $EP$ bisects $\angle BEG$ and $FP$ bisects $\angle DFG$

2. 图3:

   • Point $O$ is above $AB$
   • $FO$ bisects $\angle GFC$
   • Line segment $GE$ is extended to bisect $\angle OEA$

Questions

1. (1)

   1. In 图1, if $EG \perp FG$, find the measure of $\angle P$.
   2. In 图2, at point $Q$ below $CD$:
      • $EG$ bisects $\angle BEQ$
      • $FD$ bisects $\angle GFQ$
      • Find $\angle Q + 2\angle P$.

2. (2)

   • In 图3, with $\angle EOF + \angle EGF = 100^\circ$, write the relationship between $\angle OEA$ and $\angle OFC$.

Solution Steps

(1) ① 图1: $EG \perp FG$

• Given $EG \perp FG$, $\triangle EGF$ is a right triangle.
• Since $EP$ bisects $\angle BEG$ and $FP$ bisects $\angle DFG$:
  • $\angle BEG = 40^\circ$
  • Bisected $\angle BEG = 20^\circ$
• Let $\angle BEP = 20^\circ$ and $\angle DFP = 20^\circ$
• In right triangle $\triangle EGF$, $\angle EGF = 90^\circ$
• The measure of $\angle P$ is $180^\circ - (20^\circ + 20^\circ) = 140^\circ$

(1) ② 图2: Find $\angle Q + 2\angle P$

• Given that $EG$ bisects $\angle BEQ$ and $FD$ bisects $\angle GFQ$:
  • $\angle BEQ = 80^\circ$ (since $\angle BEQ$ is the extension of $\angle BEG$)
  • $\angle GFQ = 80^\circ$ (since $\angle GFQ$ is the extension of $\angle DFG$)
• $\angle BEQ = 40^\circ$ (bisected)
• $\angle GFQ = 40^\circ$ (bisected)
• Therefore, $\angle Q = 40^\circ$
• We already found $\angle P = 140^\circ$ from 1①.
• $\angle Q + 2\angle P = 40^\circ + 2 \times 140^\circ = 320^\circ$

(2) 图3: Relationship between $\angle OEA$ and $\angle OFC$

• Given $\angle EOF + \angle EGF = 100^\circ$:
  • Let $\angle OEA = x$
  • Since $GE$ bisects $\angle OEA$:
    • $\angle EOF + \angle EGF = x + \angle EGF = 100^\circ$
    • $\angle EGF = 100^\circ - x$
• Since $FO$ bisects $\angle GFC$:
  • $\angle OFC = 2 \times (100^\circ - x) = 200^\circ - 2x$
• Therefore, the relationship between $\angle OEA$ and $\angle OFC$ is:
  • $\angle OEA + \frac{\angle OFC}{2} = 100^\circ$

Summary

1. (1)

   1. $\angle P = 140^\circ$
   2. $\angle Q + 2\angle P = 320^\circ$

2. (2)

   • $\angle OEA + \frac{\angle OFC}{2} = 100^\circ$

Would you like more detailed steps for any part of the solution or have any other questions?

Here are some questions you might consider:

1. Can you explain how $\angle BEQ$ and $\angle GFQ$ were determined?
2. What are the properties of angle bisectors in triangles?
3. How do perpendicular lines affect angle calculations in triangles?
4. Can you illustrate more examples of angle bisectors in various geometric shapes?
5. What is the importance of parallel lines in determining angles?

Tip: Always look for symmetries and relationships in geometric figures to simplify angle calculations.