**Lesson 61**

**Objective:**

Use letters to name polygons, line, a segment, or a ray.

Use letters and the symbol to name an angle.

Use letters to name polygons, line, a segment, or a ray.

Use letters and the symbol to name an angle.

Math 4 Today

1) Write <, >, or = to 2) Brooke's recipe says

make the statement true. to sift together 5/8 teaspoon

11.437 11.473 of baking powder with 1/3

teaspoons of salt. How

many teaspoons does

Brooke sift together?

3) Rachel is putting 3,902

bagels into boxes. If she

puts 8 bagels in each box,

how many boxes can she

fill? Write the answer as a

mixed number. 4) 725 × 41 =

Naming Shapes

In geometry, we often use letters to refer to points. We can identify polygons by the points at each vertex.

To name a polygon, we start at one vertex and move around the perimeter naming each vertex in order until all vertices are named.

Naming Line Segments

We name a line by naming any two points on the line.

Naming Rays

We name a ray by naming its endpoint first and then another point on the ray.

A B

Example 1

In rectangle ABCD, name the segments perpendicular to AB. Name the parallel segments in the rectangle.

A B

D C

Example 2

The length of segment PQ is 3 cm. The length of segment PR is 8 cm. What is the length of segment QR?

P Q R

Example 3

In quadrilateral

QRST,

angle S is an acute angle. Name another acute angle in the polygon.

Q R

T S

Lesson Practice

a) Which segment is parallel to JK?

b) If JK is 10 cm long and if JM is half the length of JK, then what is the perimeter of the rectangle?

J K

M L

A

M

B

C

D

Use words to show how each of these symbols is read and draw an example of each figure:

c) BC d) CD e) PQ

Refer to the figure below to answer problems f-i.

f) Angle AMD is an obtuse angle. Use three letters, which is another way to name this angle?

g) Which angle appears to be a right angle?

h) Which ray appears to be perpendicular?

i) Name one angle that appears to be acute.

**Summarize Key Learning**

**Summarize Key Learning**

Prioritize Key Learning

Questions

New Learning

Prioritize Key Learning

Questions

New Learning

Use the coordinate plane to the right to answer the following questions.

a. Use a straightedge to construct a line that goes through points

A

and

B

. Label the line

e

.

b. Line

e

is parallel to the ______ -axis and is perpendicular to the

_______-axis.

c. Plot two more points on line

e

. Name them

C

and

D

.

d. Give the coordinates of each point below.

A:_______ B:________

C:_______ D:________

e. What do all of the points of line

e

have in common?

f. Give the coordinates of another point that would fall on line

e

with an

x

-coordinate grater than 15.

Plot the following points on the coordinate plane to the right.

P:(1 1/2, 1/2) Q:(1 1/2, 2 1/2)

R:(1 1/2, 1 1/4) S:(1 1/2, 3/4)

a. Use straightedge to draw a line to connect these points. Label the line

h

.

b. In line

h

,

x

= _____ for all values of

y

.

c. Circle the correct word.

Line

h

is parallel perpendicular to the

x

-axis.

Line

h

is parallel perpendicular to the

y

-axis.

d. What pattern occurs in the coordinate pairs that let you know that line

h

is vertical?