Q 01/05

Pi, about 3.14159, is the ratio of a circle's circumference to which of its measurements?

A) Its area

B) Its diameter

C) Its radius

D) Its longest chord

Answer · why

B) Its diameter

Because it is irrational, its decimal expansion never ends and never repeats; by the 2020s computers had calculated it to trillions of digits.

Q 02/05

In the Fibonacci sequence 0, 1, 1, 2, 3, 5, 8, 13, what number comes next?

A) 21

B) 24

C) 26

D) 34

Answer · why

A) 21

Each term is the sum of the two before it, and the pattern shows up in sunflower seed heads, pine cones and the spirals of a nautilus shell.

Q 03/05

The Pythagorean theorem says the square on which side equals the sum of the squares on the other two?

A) The height

B) The hypotenuse

C) The median

D) The base

Answer · why

B) The hypotenuse

The classic 3-4-5 triangle is the simplest whole-number example: 9 plus 16 equals 25.

Q 04/05

The interior angles of any triangle always add up to how many degrees?

A) 180

B) 240

C) 270

D) 360

Answer · why

A) 180

That is only true on a flat surface; draw a triangle on a sphere, like the Earth, and the angles add up to more.

Q 05/05

A googol is 10 raised to which power?

A) 10

B) 20

C) 50

D) 100

Answer · why

D) 100

The name was coined by a nine-year-old, mathematician Edward Kasner's nephew, and later inspired the misspelled name of a certain search engine.