The population of a city is 1,503,049. The land area of the city is 181.5 km².
What is the population density of the city?
Enter your answer in the box. Round your answer to the nearest whole number.
people/km²

A biologist is researching the population density of antelopes near a watering hole. The biologist counts 32 antelopes within a radius of 34 km of the watering hole.
What is the population density of antelopes?
Enter your answer in the box. Use 3.14 for pi and round only your final answer to the nearest whole number.
antelopes/km²

The density of mahogany wood is 0.71 g/cm3 . The volume of a piece of mahogany wood is 1728 cm³ .
What is the mass of the piece of mahogany wood?
Enter your answer as a decimal in the box.
g

Gold has a density of 19.3 g/cm3 , it is often made into a bar called a gold ingot. A certain gold ingot has a volume 51.8 cm³.
What is the mass of the gold ingot?
0.37 g
2.68 g
71.1 g
999.74 g

A block of sugar maple wood has a mass of 82.8 g and density of 0.69 g/cm3 . The block is a rectangular prism with a length of 5 cm and a width of 4 cm.
What is the height of the block of sugar maple?
Enter your answer in the box.
cm

Population density is population divided by area. So

City: 1,503,049 people / 181.5 km^2 = 8281.262 = 8281 people/km^2

Watering hole. Same thing, population divide by area. Only gotcha is the area needs to be calculated. Using A = pi r^2, you get
3.14 * (34 km)^2 = 3629.84 km^2

32/3629.84 = 0.008816 = 0 antelopes/km

Chunk of mahogany wood.
Take the volume and multiply by the density. So
1728 cm^3 * 0.71 g/cm^3 = 1226.88 g

Gold bar.
Same thing. Volume multiplied by density. So
51.8 cm^3 * 19.3 g/cm^3 = 999.74 g

And finally, the sugar maple. This one is slightly trickier. You first need to calculate the volume of the block of wood. So divide the mass by the density.

82.8 g / 0.69 g/cm^3 = 120 cm^3

Now you know the length and width are 5x4 = 20 cm^2. So calculate the height by dividing the volume by 20 cm^2. So
120 cm^3 / 20 cm^2 = 6 cm.