Here is a simple problem. Then we'll do one that requires a little more thought. The shape of a city is roughly a circle with a radius of 5 miles. If the population density for the city is 10,000 people per square mile, what is the population of the city? Now here's a problem that will stretch your problem solving skills. This time the city is also in the shape of a circle, but the population density is higher towards the center of the city and lower towards the outskirts. The numbers in the diagram represent miles. The population density is 10,000 people per square mile in the inner circle. In the first ring out from the center the density is 8,000 people per square mile, the second ring out it's 6,000, in the third ring out it's 4,000 and in the largest ring it's only 2,000 people per square mile. Finally, here is a three dimensional problem. Density is defined as weight per unit of volume. So which weighs more, a ball of zinc with a radius of 3 cm, or a ball of chromium with a radius of 2.99 cm? (You'll need to do a little research to discover the density of these elements.)

Here is a simple problem. Then we'll do one that requires a little more thought. The shape of a city is roughly a circle with a radius of 5 miles. If the population density for the city is 10,000 people per square mile, what is the population of the city? Now here's a problem that will stretch your problem solving skills. This time the city is also in the shape of a circle, but the population density is higher towards the center of the city and lower towards the outskirts. The numbers in the diagram represent miles. The population density is 10,000 people per square mile in the inner circle. In the first ring out from the center the density is 8,000 people per square mile, the second ring out it's 6,000, in the third ring out it's 4,000 and in the largest ring it's only 2,000 people per square mile. Finally, here is a three dimensional problem. Density is defined as weight per unit of volume. So which weighs more, a ball of zinc with a radius of 3 cm, or a ball of chromium with a radius of 2.99 cm? (You'll need to do a little research to discover the density of these elements.)