Download 2.5 Proving Angles Congruent

Miss Stanley
The Green School
Geometry Fall 2011
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Lesson 2.5 Proving Angles Congruent
If 4x and (3x + 5) are vertical angles. Find the value of x.
Draw a picture of the vertical angles.
Solve for x.
(5x – 20) and (3x + 8) are vertical angles. (5x + 4y) and (5x – 20) are supplementary angles. Find x and y.
Draw a picture of the vertical and supplementary
angles.
Solve for x.
Plug in your value of x to solve for y.
Angle 1 and Angle 3 are Complementary. Angle 2 and Angle 3 are Complementary.
Prove Angle 1 is Congruent to Angle 2.
STATEMENT
JUSTIFICATION
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3x and (80 – x) are vertical angles. Find the value of x.
Draw a picture of the vertical angles.
Solve for x.
3x and 75 are vertical angles. 75 and y are supplementary angles. Find the value of x and y.
Draw a picture of the vertical and supplementary
angles.
Solve for x.
Plug in your value of x to solve for y.
Find the value of x.
Find the value of x.
GIVEN: Angle FED and Angle DEW are complementary.
PROVE: Angle FEW is a right angle.
Draw a picture of these angles.
Now prove angle FEW is a right angle.
STATEMENT
JUSTIFICATION
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Find the value of x and y.