Question

Crater lake in Oregon is shaped like a circle with a diameter of about 5.5 miles.

How far is it around the perimeter of crater lake?

Answer 1

Perimeter of the circle is 2π(radius)

=2πr

=π(2r)

=π×Diameter

`(\pi * 5.5 )\: miles = 3.14 * 5.5 \\ = 17.27 \: miles`

17.27 miles is the right answer.

Answer 2

C ≈ 17.27 mi

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Geometry

Circumference Formula: C = πd

• C is circumference
• d is diameter

Explanation:

*Note: The perimeter of a circle is the circumference.

Step 1: Define

Diameter d = 5.5 mi

Step 2: Find C

1. Substitute [CF]: C = π(5.5 mi)
2. Multiply: C = 5.5π mi
3. Evaluate (~3.14): C ≈ 17.27 mi