Section C: Practice Problems Let’s Put it to Work

Section Summary

Details

In this section, we solved problems and puzzles by converting units of measurement—gallons, quarts, cups, pounds, ounces, yards, feet, and inches—and by comparing measurements in different units. We saw that the problems could be solved in different ways.

For example, if Priya threw a frisbee 16 yards and this is 4 times as far as the distance Jada threw in feet, how far did Jada throw the frisbee?

One way to solve this problem is by finding $16 \div 4$ to find Lin’s throw distance in yards ( $16 \div 4 = 4$ ) and then multiplying the result to convert the yards to feet ( $4 \times 3 = 12$ , so 4 yards is 12 feet).
Another way is to first convert the 16 yards to feet ( $16 \times 3 = 48$ , so 16 yards is 48 feet) and then divide the result by 4 to find Lin’s throw distance ( $48 \div 4 = 12$ ).

In the last two lessons, we solved multiplication and comparison problems that involve the perimeter of rectangles and some other quadrilaterals.

Problem 1 (Lesson 14)

Jada’s class drank 2 gallons of milk at lunch. How many cups is that?
The third graders at Jada’s school drank 3 times as much milk as Jada’s class. How many quarts is that?

Problem 2 (Lesson 14)

A rectangle has perimeter 19 cm. One side is 4 cm. How long is the other side of the rectangle?
A square has perimeter 19 cm. How long is each side of the square? Explain or show your reasoning.

Problem 3 (Lesson 15)

Diego saw a snake that is 9 inches long at the pet store. The world’s longest snake, a python, is 10 yards long. How many times longer is the python than the snake Diego saw? Explain or show your reasoning.

Problem 4 (Lesson 16)

Andre drew a rectangle that is 5 centimeters long and 6 centimeters wide. What is the perimeter of Andre’s rectangle?
Jada drew a rectangle whose side lengths are 4 times as long as those of Andre’s rectangle. What is the perimeter of Jada’s rectangle?

Problem 5 (Exploration)

A furlong is 220 yards. It is a unit usually used to measure the distance of horse races. A mile is 5,280 feet. Mai read that a furlong is $\frac{1}{8}$ mile. Is this true? Explain or show your reasoning.

Problem 6 (Exploration)

Many of the length measurements that we use today have interesting histories. Choose one of them, such as a foot, a yard, or a marathon and investigate its origin.