BELLRINGER

BELLRINGER Write this on the back on your foldable Congruent segments are segments that have the same length. In the diagram, PQ = RS. Tick marks are used in a figure to show segments of equal length.

Midpoint

Segment Bisector

What is an angle?

Bellringer Have your foldable and homework out on your desk!

Angles An angle is a figure formed by two rays with the same endpoint. pg. 790 An angle is a figure formed by two rays with the same endpoint. The common endpoint is called the vertex of the angle. The rays are the sides of the angle. vertex

Naming Angles A C B D H F Ask a student to pick an angle and tell another student which one she is thinking of. I G E

Naming Angles A C B D H F Ask a student to pick an angle and tell another student which one she is thinking of. I G E

Naming Angles A C B D H F Ask a student to pick an angle and tell another student which one she is thinking of. I G E

Give Four Ways to Name this Angle pg. 790 Give Four Ways to Name this Angle J 1 K If you can give me four ways to name this angle, we’re doing good. L

Write the different ways you can name the angles in the diagram. RTQ, STR, 1, 2

pg. 791

Angle

On back of foldable! Congruent angles are angles that have the same measure. In the diagram, mABC = mDEF. Arc marks are used to show that the two angles have equal measures.

ABC refers to the angle mABC refers to the measurement of the angle A Distinction! ABC refers to the angle mABC refers to the measurement of the angle

Angle Bisector

Measuring Angles pg. 791 The measure of an angle is usually given in degrees. Since there are 360° in a circle, one degree is 1/360 of a circle. We can use protractors to measure angles.

Let’s play with protractors! Construct a 50 degree angle. Construct a 35 degree angle that faces up like a v. Construct a 120 degree angle.

Postulate

What is AC? What is DF? If three points are collinear, then the lengths of the two shorter segments equals the length of the larger segment. 12 4 A B C E 7 13 D F

Segment Addition Postulate pg. 777 Let A, B, and C be collinear points. If B is between A and C, then AB + BC = AC Notice: this means the length of segment AB plus the length of segment BC equals the length of segment AC A B C

G is between F and H, FG = 6, and FH = 11. Find GH. FH = FG + GH 11 = 6 + GH – 6 –6 5 = GH F G H

E is between D and F. Find DF. x = 4 DF = 24

S is the midpoint of RT. Find RS, ST, and RT. R S T –2x –3x – 2 RS = 4 ST = 4 RT = 8

Angle Addition Postulate pg. 792 If S is in the interior of PQR , then mPQR = mPQS + mSQR .

mXWZ = 121° and mXWY = 59°. Find mYWZ. mYWZ = mXWZ – mXWY  Add. Post. mYWZ = 121 – 59 Substitute the given values. mYWZ = 62 Subtract.

KM bisects JKL. Find mJKM. (4x + 6)° (7x – 12)° mJKM = 30°

Bellringer Have your homework out on your desk! (pg 37 #1-7)

Group Work Work with a table partner on the activity