Math Problem of the Month

Welcome to the Math Problems of the Month Page. For each month, I will feature a math problem by which I myself create. Every month will have a different problem with an answer posted at the end of the month. Feel free to discuss on a forum so that those who don't understand might get it better. The difficulty will vary: some will be easy, and some will be challenging. Some problems will require some logical thinking. The list is cumulative, so have fun with past problems and indulge in the challenge of the new!

# 2008

## September

A circle has a circle within it. The larger circle's radius is congruent to the smaller circle's circumference. The circumference of the larger circle is 12.4 centimeters. What is the measure of area between the two circles' boundaries?

## October

Four different colored balls weigh different amounts. The red ball weighs the same of the combined weight of the blue and yellow balls. The lightest ball weighs as much as the green ball when a red ball is combined with the lightest ball's weight. All the balls combined weigh 20 pounds. The blue ball's weight is twice the yellow ball's weight. What is the weight of each ball?

## November

On a sphere of radius 3.82 feet, what is the area of an equilateral triangle with a side length of six feet on the surface?

## December

Although this is not the case, if Christmas was on a Thursday in 2015, what day was Christmas on in 1980?