Given that lines a and b are parallel and that m∠4 = 128°, find m∠7.

lines a and b are parallel. finding the measure of angle 7

Solution:

Given, a and b are parallel lines.

The measure of angle 4 = 128°

We have to find the measure of angle 7.

Since the given lines are parallel, corresponding angles are equal.

∠4 = ∠8

So, m∠8 = 128 degrees.

We know that the linear pair of angles are always supplementary.

From the figure, ∠7 and ∠8 form the linear pair of angles.

So, ∠7 + ∠8 = 180

∠7 + 128 = 180

∠7 = 180 - 128

∠7 = 52 degrees.

Therefore, the measure of angle 7 is 52 degrees.

Given that lines a and b are parallel and that m∠4 = 128°, find m∠7.

Summary:

Given that lines a and b are parallel and that m∠4 = 128°, then m∠7 is 52 degrees.

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