Q 01/05

What is the sum of the interior angles of any triangle?

A) 90 degrees

B) 180 degrees

C) 360 degrees

D) 720 degrees

Answer · why

B) 180 degrees

180 degrees: draw a line through one corner parallel to the opposite side and the three angles sit side by side along it, filling exactly half a turn.

Q 02/05

Which of these numbers is prime?

A) 9

B) 19

C) 39

D) 81

Answer · why

B) 19

19 is prime because nothing but 1 and itself divides it evenly; 9 and 81 are powers of 3, and 39 is 3 × 13.

Q 03/05

In algebra, what kind of equation is y = 3x + 2 an example of?

A) Quadratic

B) Exponential

C) Logarithmic

D) Linear

Answer · why

D) Linear

Linear: x appears only to the first power, so it plots as a straight line, here climbing 3 units for each step right and crossing the y-axis at 2.

Q 04/05

In calculus, what concept measures the instantaneous rate of change of a function?

A) Derivative

B) Limit

C) Asymptote

D) Integral

Answer · why

A) Derivative

Derivative: it gives the slope of a curve at a single point, which is why a car's speed at any instant is the derivative of the distance it has covere...

Q 05/05

Which fraction has long been used as a handy stand-in for pi?

A) 7/22

B) 11/7

C) 22/7

D) 44/7

Answer · why

C) 22/7

22/7 comes from Archimedes, who trapped pi between 223/71 and 22/7 by fitting 96-sided polygons inside and outside a circle.