# Lines and Angles

### Learning objectives

1. Understanding Exterior and Interior angles and their dependency
2. Understanding that a triangle is a planar fig formed by the intersection of three lines
3. Understanding Triangle as a plane which covers area

### Problem description

#### Exercise 6.3

1. In Fig. 6.39, sides QP and RQ of ∆ PQR are produced to points S and T respectively. If ∠ SPR = 135° and ∠ PQT = 110°, find ∠ PRQ.

### Activity No # 1

• Estimated Time - 40 minutes
• Materials/ Resources needed; Paper, pencil, and scale.
• Prerequisites/Instructions, if any:
1. The students should know points and line segments.
• Multimedia resources
• Website interactives/ links/ Geogebra Applets
• Process (How to do the activity):

Display the GGB file first in which Angle SPR and PQT is already set to given measurements. and it would be helpful to ask the following questions which helps to understand the prior learning of children which might take 1 or 2 minutes.

1. In the given applet identify the Triangle gives.
2. Name the sides and Angles of the Triangle
3. Identify the interior and exterior angles
4. Measure the angle adjacent to 1350 (What is the sum of 1350 and its adjacent angle.If the answer is 1800 a teacher can ask the reason)
5. Measure the angle adjacent to 1100 (What is the sum of 1350 and its adjacent angle If the answer is 1800 a teacher can ask the reason)

If the answer is different then use the angle measure tool in the GGB file and measure the adjacent angles of

1. Developmental Questions (What discussion questions):
• Evaluation (Questions for assessment of the child):