Circle Basics
What part of a circle goes from the center to the edge?
The Radius.
Which formula finds the distance around a circle?
C=3.14*D
Find the circumference when the diameter is 10 units.
31.4 Units
Find the area of a circle with a radius of 2 units.
12.56 Units^2
What does it mean to decompose a shape?
Brake into smaller shapes.
Which is Longer; the radius or the diameter? Explain why?
The Diameter because its made of two radii
Which formula finds space inside a circle?
A=3.14*R^2
Find the circumference when the radius is 3 units.
18.84 Units
Find the area of a circle with a radius of 4 units.
50.24 Units^2
Why do we find areas of pieces before adding?
Easier to calculate step by step.
If the radius is 4 units, how long is the diameter?
8 Units
You are given a diameter. Which formula do you start with?
Circumference because the diameter is already provided.
A circle has a diameter of 8 units. Write the circumference in terms of PI.
8*PI
A circle has a diameter of 6 units. What must you find first to get the area?
What is the density of water??
Come on guys what if Mr.Beast was here...
1 Gram per cubic centimeter.
...Mr.Beast left
True or False?
Every line across a circle is a diameter.
False. Only every line passing through the center and from edge to edge of the circle.
You are given a radius. Which formula is easiest to use and why?
Area because the radius is already given.
A circle has a radius of 5 units. Write the circumference in terms of PI.
10*PI
Write the area of a circle with a radius of 5 units in terms of PI.
25*PI
Which measurement do you usually find first? The area of parts or total perimeter? Why?
Area of parts usually first.
Explain how radius and diameter are related using words ( no numbers ).
The diameter is twice the radius/ the radius is half of the diameter.
A student uses the area formula to find the distance around a track. What went wrong?
A student multiplies PI by the radius instead of the diameter. What mistake did they make?
They multiplied by the radius not the diameter.
A student forgets to square the radius. Explain why this matters.
if you don't square the radius, the area will be to small and incorrect.
Explain a step by step plan to solve any composite figures problems.
1. Decompose
2.Solving Pieces
3.Combine
4.Check answer