Download Geometry 15.09.16 CP1

1-4 Pairs of Angles
WARM-UP – 1 Pt Each Effort / 2 Pts Right
Find the circumference and area of each circle.
Leave answers in terms of .
1. radius 2 cm
2. diameter 12 ft
3. The area of a rectangle is 48 in2, and the
length is 12 in. Find the width & perimeter.
Holt McDougal Geometry
1-4 Pairs of Angles
Area of Triangle
A = ½ b*h
A = ½ (6cm) * (6cm)
A = 18 cm2
6√2 cm
6 cm
A = ½ 6√2*3√2
A = ½ 6√2cm*3√2cm
3√2 cm
6 cm
Holt McDougal Geometry
A = 18 cm2
1-4 Pairs of Angles
Plan for the week:
Monday
Finish Angle Pair Review
Tuesday
Angle Pair Quiz
Begin Perimeter & Area
Wednesday
Continue Perimeter & Area
Thursday
Continue Perimeter & Area
Friday
Continue Perimeter & Area
Holt McDougal Geometry
1-4 Pairs of Angles
Holt McDougal Geometry
1-4 Pairs of Angles
DON’T FORGET
Keep your units; and add or multiply
them accordingly.
in + in = in
in * in = in2
Holt McDougal Geometry
1-4 Pairs of Angles
Pick a base b on any
side of a triangle.
The height h is
perpendicular to the
base to the opposite
vertex.
Holt McDougal Geometry
1-4 Pairs of Angles
In a circle a diameter is a segment that
passes through the center of the circle and
whose endpoints are on a circle. A radius of
a circle is a segment whose endpoints are the
center of the circle and a point on the circle.
The circumference of a circle is the distance
around the circle.
Holt McDougal Geometry
1-4 Pairs of Angles
The ratio of a circle’s circumference to its
diameter is the same for all circles. This ratio
is represented by the Greek letter  (pi). The
value of  is irrational. Pi is often
approximated as 3.14 or
.
Holt McDougal Geometry
1-4 Pairs of Angles
Example 3: Finding the Circumference and
Area of a Circle
Find the circumference and area of a circle with
radius 8 cm.
cm
Holt McDougal Geometry
cm2
1-4 Pairs of Angles
Check It Out! Example 3
Find the circumference and area of a circle
with radius 14m.
m
Holt McDougal Geometry
m2
1-4 Pairs of Angles
Lesson Quiz: Part I
Find the area and perimeter of each figure.
1.
2.
x2 + 4x; 4x + 8
3.
10x; 4x + 16
Holt McDougal Geometry
23.04 cm2;
19.2 cm