Find the distance between the points below(9, 0) and (5,2)

Find the length of the hypotenuse if the length of the legs are 4 and 2

The circumference of a circle is

The distance around a circle

First we must define some things about a circle.

The radius is the distance from the center of a circle to any point on a

circle.

The diameter is the distance across a circle through the

center.

We use Pi as the measurement to help us find the circumference of a circle.

Pi, not Pie!

Two formulas are used in finding the circumference of a

circle.

Circumference = d

WHEN THE CIRCLE HAS A DIAMETER MEASUREMENT, USE THE FOLLOWING FORMULA.

4in.

Circumference = 2 r

When the radius of a circle is given, the following formula

should be used.

5 in

Tell me what formula would be used to solve the next five problems.

3in

C =

8ft

C =

122mm

C =

17.5 cm

C =

Find the perimeter of this shape

Use π = 3.14 to find perimeter of this shape.

The perimeter of this shape is made up of the circumference of a circle of diameter 13 cm and two lines of length 6 cm.

6 cm13 cm

Formula for the area of a circle

We can find the area of a circle using the formula

radius

Area of a circle = πr2

Area of a circle = π × r × r

or

The circumference of a circle

Use π = 3.14 to find the area of this circle.

A = πr24 cm

Finding the area given the diameter

The radius of a circle is half of its radius, or

We can substitute this into the formula

A = πr2

r = d2

The area of a circle

Use π = 3.14 to find the area of the following circles:

A = πr22 cm A = πr210 m

A = πr2

23 mm

A = πr278 cm

Find the area of this shape

Use π = 3.14 to find area of this shape.

The area of this shape is made up of the area of a circle of diameter 13 cm and the area of a rectangle of width 6 cm and length 13 cm.

6 cm13 cm

Holt McDougal Geometry

10-3Composite Figures

A composite figure is made up of simpleshapes, such as triangles, rectangles,trapezoids, and circles.

To find the area of a composite figure, find the areas of the simple shapes and then use the Area Addition Postulate.

Holt McDougal Geometry

10-3Composite Figures

Find the shaded area. Round to the nearest tenth, if necessary.

Example 1A: Finding the Areas of Composite Figures by Adding

Holt McDougal Geometry

10-3Composite FiguresCheck It Out! Example 1

Find the shaded area. Round to the nearest tenth, if necessary.

Holt McDougal Geometry

10-3Composite FiguresExample 2: Finding the Areas of Composite Figures by

SubtractingFind the shaded area. Round to the nearest tenth, if necessary.

Holt McDougal Geometry

10-3Composite FiguresCheck It Out! Example 2

Find the shaded area. Round to the nearest tenth, if necessary.