# Circles Review Unit 9.

## Presentation on theme: "Circles Review Unit 9."— Presentation transcript:

Circles Review Unit 9

Standards Standard 78: Identify and describe relationships among circles (radius, diameter, chord, tangent, secant, etc.) Standard 79: Find the relationships between congruent and similar circles. Standard 80: Solve problems involving tangents of circles. Standard 81: Measure central angles and arcs of circles. Standard 82: Describe relationships between adjacent arcs as well as between arcs and chords. Standard 83: Find the lengths of chords in a circle. Standard 84: Find the measure of arcs in a circle. Standard 85: Determine the area and circumference of a circle. Standard 86: Determine the area and circumference of a sector of a circle.

Standard 78: Identify and describe relationships among circles (radius, diameter, chord, tangent, secant, etc.) Draw a circle and label each of the following: Radius Diameter Chord Tangent Secant Center

Standard 80: Solve problems involving tangents of circles.
Draw four circles and label them 1- 4. Draw an internal tangent between circles 1 and 3. Draw an external tangent between circles 2 and 4.

Standard 81: Measure central angles and arcs of circles.
Draw a circle with a central angle of 45 degrees. Draw a circle with a radius of 12 feet and a central angle of 215 degrees.

Standard 82: Describe relationships between adjacent arcs as well as between arcs and chords.
What is the relationship between adjacent arcs? What is the relationship between congruent arcs? Draw a picture of both.

Standard 84: Find the measure of arcs in a circle.
Given the circle, draw an arc of 78 degrees.

Standard 85: Determine the area and circumference of a circle.
What is the formula for the area of a circle? What is the formula for the circumference of a circle?

Standard 85: Determine the area and circumference of a circle.
There is a circle with a radius of 30 feet. What is the area of the circle? What is the circumference of the circle?

Standard 86: Determine the area and circumference of a sector of a circle.
What is the formula for the area of a sector of a circle? What is the formula for the circumference of a sector of a circle?

Standard 86: Determine the area and circumference of a sector of a circle.
There is a circle with a radius of 30 feet and a sector of 38 degrees. What is the area of the sector? What is the circumference of the sector?