Lines, rays and right angles
Use the worked example and teaching sequence below to explain the reasoning before independent practice.
Use New Numbers to make another set. Choose Worksheet or Answer Key, then use the worksheet’s Print button.
Teaching Notes
Use the worked example and teaching sequence below to explain the reasoning before independent practice.
Before You Begin
- Recognize a vertex and two rays.
Teaching Steps for Parents and Teachers
- Put the protractor center on the vertex.
- Align one ray with the zero line.
- Read the scale starting at that zero, or mark the required measure and draw the second ray.
Worked Examples
Two adjacent angles measure 35° and 25°. Find their combined angle.
- The adjacent angles do not overlap.
- Add their measures: 35 + 25 = 60.
Answer: 60°
Common Mistakes and How to Help
Start from the correct zero on the protractor; do not choose the other scale.
Is the result acute, right, or obtuse, and does that fit the drawing?
Questions to Check Understanding
- Is the result acute, right, or obtuse, and does that fit the drawing?
- What in the numbers or diagram supports your answer?
Practice Advice
Work through the example together. Ask the learner to explain the first two problems, then try three independently. Review the first incorrect step before assigning more practice.
Next Practice
- Use New Numbers to practice the same skill with different values.
- If the learner needs help, return to the example and model each step before trying again.