Download 5-6: Proving Lines Parallel Day 2

Geometry/Trig
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Lesson 5-6: Proving Lines Parallel Day 2
Learning Goal: #3: How can we justify whether or not lines are parallel using angles?
Warm up
1. Let’s look at the following student work and answer the questions below:
The m∠1 = 59 degrees and m∠8 = 59 degrees. Justify whether or not x and y are parallel.
What did Meredith do well in this problem
Wha What suggestions could we give to
and in her explanation?
Meredith to improve her explanation?
Let’s try one:
2. Is line A parallel to line B? Justify your answer!
The labeled angles are __________________________ (type),
therefore, they must be ________________________ (relationship)
when the lines are parallel. The angles are _________________________,
so the lines ___________________ parallel.
Geometry/Trig
̅̅̅̅ is parallel to 𝐶𝐷
̅̅̅̅ .
1. Use the information provided in the picture below to prove that 𝐴𝐵
HINT:
Use the
triangles to
help you fill in
some missing
angles!
Can you
identify/use
any angle
relationships?
Practice
2. Is AB parallel to CD? Justify your answer!
Remember to write a clear and
thorough explanation! Use the
model in our notes to help us!!
3. Find the value of x that would make a parallel to b. Explain how you arrived at your answer.
Geometry/Trig
4. Determine whether each pair of lines is parallel. Be sure to justify your answer!
(a)
5. Find the measure of angles 1, 2, and 3.
𝑚∠1 =
𝑚∠2 =
𝑚∠3 =
6. Solve for x:
(b)
Geometry/Trig
7. Using the information provided in the diagram and
your knowledge of angles, find the measure of
ALL missing angles.
𝑚∠1 =
𝑚∠7 =
𝑚∠2 =
𝑚∠8 =
𝑚∠3 =
𝑚∠9 =
𝑚∠4 =
𝑚∠10 =
𝑚∠5 =
𝑚∠11 =
𝑚∠6 =
𝑚∠12 =
8. Two vertical angles measure x and 45°. How many degrees are there in x?
9. Two complementary angles measure x and 65°. How many degrees are there in x?
10. Using the diagram below…Don’t forget to use three letters!!
(a) Name a pair of supplementary angles.
(b) Name a pair of vertical angles.
Geometry/Trig
11. Solve for angles a, b, c in the diagram below. Show your work clearly!
12. Solve for the missing angle. Show your work clearly!