Area of a circle is πr^2.
The radius of the smaller circle with diameter 10 cm is 5 cm.
The radius of the larger circle with diameter 20 cm.is 10 cm.
Area of larger circle : Area of smaller circle
Area of larger circle = 100π.
Area of smaller circle = 25π.
Ratio = 100π : 25π or 100π/25π.
Answer:

General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Algebra I</u>
- Average Rate of Change:

Step-by-step explanation:
<u>Step 1: Define</u>
Interval -1 ≤ x ≤ 3
a = -1, b = 3
f(a) = f(-1) = 4
f(b) = f(3) = -4
<u>Step 2: Find Average</u>
- Substitute in variables [ARC]:

- Substitute:

- [Fraction] Subtract/Add:

- [Fraction] Divide:

1/2 because there are 3 odd numbers on a number cube and 6 numbers in total and 3/6 simplified is 1/2