TODAY IN GEOMETRY…

STATs for Ch.3.1-3.3 Quiz

Learning Goal 2: 3.4 Calculate Parallel and Perpendicular Slopes with a graph and algebraically

Independent Practice

HOW DID YOU “SHAPE” UP??Results for ALL of my Geometry classes:

GRADE NUMBER OF STUDENTS WHO TOOK THE CH.3 QUIZ (17 pts.)

1ST PERIOD 3RD PERIOD 5TH PERIOD 6TH PERIOD TOTAL

A 2 7 7 6 22B 5 9 11 6 31C 6 8 4 7 25D 4 5 1 6 16F 6 0 2 2 10

Avg. 22.54 25.97 26.70 24.91 25.03

KINDS OF SLOPES

UNDEFINED

ZERO

POSITIVE INCREASING

NEGATIVE DECREASING

FORMULA FOR SLOPE:

Used in GraphingUsed when given two points and

REVIEW:

CALCULATING SLOPE WITH A GRAPH

Find the slope of AB

A

B

−𝟓

𝟑

Find two points that are on crosshairs. (exact points)

negative slope = downPositive slope = up

𝑠𝑙𝑜𝑝𝑒=−53

=−53

PRACTICE: Find the slope of the given line.

𝑠𝑙𝑜𝑝𝑒=11

𝟏𝟏

PRACTICE: Find the slope of the given line.

−𝟏𝟐

𝑠𝑙𝑜𝑝𝑒=−12

REVIEW:

CALCULATING SLOPE GIVEN TWO POINTS

Find the slope of AB: A(-2 , 8) B(3 , 2)

𝑥1 , 𝑦1 𝑥2 , 𝑦 2

PREDICT: Do you expect to have an increasing or decreasing slope? NEGATIVE = DECREASING SLOPE

Find the slope of CD: C(5,-2) D(-4,1)

𝑥1 , 𝑦1 𝑥2 , 𝑦 2

PREDICT: Do you expect to have an increasing or decreasing slope? NEGATIVE = DECREASING SLOPE

REVIEW:

SLOPE STEEPNESS

Which line is steeper?

𝑨

𝑩𝑫

𝑪𝑬

𝑭

𝑯

𝑮

−𝟑

−𝟐𝟓

𝟏

𝟒

Greater the absolute value of the slope = steeper

SLOPES OF PARALLEL AND PERPENDICULAR LINES

Under slopes you may also include:

PARALLEL LINES: Two lines that have the same slope.

Ex.

PERPENDICULAR LINES: Two lines that have negative reciprocal slopes. Ex.

Which of the following lines are parallel or perpendicular?

A

B

C

D

E

F

−53

−53

35

Give the PARALLEL and PERPENDICULAR slopes for the following lines.

1. 2. 3.

4. 5. 6.

Parallel Slope:

Perpendicular:

Parallel Slope:

Perpendicular:

Parallel Slope:

Perpendicular:

Parallel Slope:

Perpendicular:

Parallel Slope:

Perpendicular:

Parallel Slope:

Perpendicular:

Line m passes through ( -1 , 3) and (4 , 1). Line t passes through (-2 , -1) and (3 , -3). Are the two lines parallel, perpendicular or neither.*To determine if slopes are you must calculate slope for each line.

have equal slopes, so the two lines are parallel.

Line passes through (3 , 0) and (7 , 6). Graph the line perpendicular to that passes through the point ( 2, 5).*To calculate the perpendicular slope, you must determine the slope first.

𝒍𝒊𝒏𝒆𝒉(𝟐 ,𝟓)

−23

HOMEWORK #4:

Pg. 175: 1-27 odd 28-30

If finished, work on other assignments:

HW #1: Pg. 150: 11-15, 18-23, 24-32, 43-44HW #2: Pg. 157: 4-19, 22-24, 27-31, 33, 35, 36HW #3: Pg. 165: 3-15, 19-21, 23, 26, 27