Bell Work 11/28/12 Classify each triangle using angles and sides. 1)2) Write an equation for a line with the following: 3) parallel to:4) perpendicular.

Bell Work 11/28/12• Classify each triangle using angles and sides.

• 1) 2)

• Write an equation for a line with the following: • 3) parallel to: 4) perpendicular to:

y = 3x – 4; y-int at 5 y = -1/2x + 4 through (2, 1)

Outcomes

• I will be able to:

• 1) Identify congruent figures and their corresponding parts

• 2) Prove that two triangles are congruent

• 3) Write a congruence statement

Congruence• What does it mean for two figures to be

congruent?• Congruence Investigation:• 1) Open Geometry Pad• 2) Plot each triangle• 3) Find the measure of the angles and sides• 4) Determine if the triangles are congruent• 5) Decide what it means for figures to be

congruent

Congruent Figures

Two figures are congruent if they have the exact same size and shape

The corresponding parts of congruenttriangles are always congruent.

DEFABC

FC DA EB So,

Congruence Statement

• Congruence Statement: A symbolic statement in which we write what figures are congruent.

• ***Be sure corresponding parts line up!!!

Congruent Figures Example 1a

Congruent Figures Example 1b

• Circle the figures that look congruent

Congruent Figures Example 2

Remember, corresponding partsmust be congruent!!!

ACBJPL

Congruent Figures Example 3

What do we know about angle A andangle D?

So, how can we solvefor x? 5x + 2 = 87

5x = 85x = 17

What do we knowabout angle B and E?

How can we solve for y?87 + 42 + 3y = 180

3y = 51y = 17

Third Angles Theorem

If two angles of one triangleare congruent to two angles inanother triangle, then the third angles arecongruent.

Angle A = 57Angle B = 90Angle C = x

Angle D 57Angle E = 90Angle F = 33

Without doing any math, how can we find C?

x = 33

Third Angles Example 1

What do we know about Mand T?

They are congruentHow can we find x?

55 + 65 + 2x + 30 = 1802x = 30x = 15

Quiz Friday

• Quiz will cover:• 1) Writing equations of parallel and

perpendicular lines• 2) Determining if two lines are parallel• 3) Solving for variables in parallel lines• 4) Classifying triangles

White Board Quiz Review

• 1) Find the variables

• X = 12 • Y = 11


• 2) Write an equation of the line parallel to:• y = 1/4x – 5 with a y-intercept of -11

• y = 1/4x -11


• 3) Write an equation of the line perpendicular to: y = 1/3x + 4 through (-1, 5)

• (y – 5) = -3(x + 1)• or y = -3x + 2


• 4) Are the lines parallel? Explain why/why not

• Yes, corresponding angles are congruent


• 5) Are the lines parallel? Explain why/why not.

• No, same side interior angles are congruent. They should add to 180°.


• 6) Write the equation of the line parallel to: y = 1/5x + 10 through (0, -5)

• (y + 5) = 1/5(x – 0)• or y = 1/5x - 5


• 7) Are the lines parallel? Explain why/why not.

• No, same side interior angles do not add to 180°


• 8) Classify the following triangle using its sides and angles

• Acute Scalene Triangle


• 9) Classify the following triangle using its sides and angles.

• Right Scalene Triangle


• 10) Classify the following triangle using its sides and angles

• Equiangular equilateral triangle• Could also be classified as isosceles or acute

Exit Quiz

Bell Work 11/28/12 Classify each triangle using angles and sides. 1)2) Write an equation for a line with the following: 3) parallel to:4) perpendicular.

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