Famous mathematicians
Number Theory
Geometry
Riddles
100

E = mc2

Einstein

100

Define  to be  for all real numbers  and  What is the value of

-2

100

At a store, when a length or a width is reported as  inches that means it is at least  inches and at most  inches. Suppose the dimensions of a rectangular tile are reported as  inches by  inches. In square inches, what is the minimum area for the rectangle?

3.75

100

If there are four apples and you take away three of them, how many apples do you have?

3

200

a2 + b= c2

Pythagoras

200

Cities  and  are  miles apart. Alicia lives in  and Beth lives in . Alicia bikes towards  at 18 miles per hour. Leaving at the same time, Beth bikes toward  at 12 miles per hour. How many miles from City  will they be when they meet?

27

200

The sum of two angles of a triangle is  of a right angle, and one of these two angles is  larger than the other. What is the degree measure of the largest angle in the triangle?


72

200

A couple went for a picnic. They have 5 sons and each son has three sisters. Each sister has one baby. In total how many people went for the picnic?

13

300

         1 

       1   1 

      1  2  1

    1  3   3  1

1    4   6  4   1

Pascal

300

The  integers from  to  inclusive, can be arranged to form a -by- square in which the sum of the numbers in each row, the sum of the numbers in each column, and the sum of the numbers along each of the main diagonals are all the same. What is the value of this common sum?

10

300

Six points are equally spaced around a circle of radius 1. Three of these points are the vertices of a triangle that is neither equilateral nor isosceles. What is the area of this triangle? 

Hint: draw it!

√3 / 2

300

If Reema is the 50th fastest and 50th slowest runner in her school. How many students are there in the school?

99

400

0, 1, 1, 2, 3, 5, 8, 13, 21, 34... 

Fibonacci

400

How many digits are in the base-ten representation of

Hint: factor

18

400

A  right triangle is inscribed in circle , and a  right triangle is inscribed in circle . What is the ratio of the area of circle  to the area of circle ? (Draw it out!)

Hint: Thale's theorem states that if A, B, and C are distinct points on a circle where the line AC is a diameter, the angle ∠ ABC is a right angle. 

25/169

400

You want to boil an egg for two minutes. If there is only a three-minute timer, a four-minute timer, and a five-minute timer, how can you boil the egg for two minutes only?

Start 3 min timer and 5 min timer w/out boiling egg yet. When 3 min timer ends put egg in to boil and take out when 5 min timer ends.

500

ln(e) = 1

e = 2.71828...

Euler

500

How many three-digit positive integers  satisfy the following properties?

  • The number  is divisible by .
  • The number formed by reversing the digits of  is divisible by .

14

500

A rectangular parking lot has a diagonal of  meters and an area of  square meters. In meters, what is the perimeter of the parking lot?

Hint: use binomial expansion (a+b)2 = ...

62

500

How can you get 720 by using six zeros and any mathematical operator?

(0!+0!+0!+0!+0!+0!)!


= (1+1+1+1+1+1)! = 6! = 720