Mathletics and Measurements

Question 1

What are the qualifications for a number to be considered prime?

Answer 1

A number is prime if it is divisible by only 1 and itself.

For example, 11 is prime, since its only factors are 1 and 11. The opposite of a prime number is called a composite number. 10 is not prime, and would therefore be categorized as composite, since its factors include 1, 2, 5, 10.

Exceptions:

0 is neither prime nor composite.
1 is neither prime nor composite. A common misconception is that 1 is prime, but it is not technically “divisible by 1 AND itself.”

Question 2

Radius

Answer 2

The distance from the center of a circle to its edge.

Question 3

Why do we use Roman numerals and how do you read them?

Answer 3

Roman numerals originated as a counting system in ancient Rome. These characters are still prevalent in architecture, but also in more modern-day applications (e.g. Super Bowl XLVIII).

The seven numerals used today:

I - 1
V - 5
X - 10
L - 50
C - 100
D - 500
M - 1000
Roman numerals are written largest to smallest. If a smaller number is placed before a larger one, that value should be subtracted from the larger one. For example: IX is 9 (10-1).

Question 4

When measuring angles, how are degrees and radians different?

Answer 4

Degrees are mathematically abstract (not meaningful numbers), whereas radians have mathematical basis.

For example, a circle is arbitrarily divided into 360 degrees, but in radians is measured as as 2π. Radians are used in actual calculations. Degrees are typically used for more practical purposes such as navigation (e.g. the turn is 90 degrees to the left).