# Lesson 12

Interpreting Points on a Coordinate Plane

### Problem 1

The elevation of a submarine is shown in the table. Draw and label coordinate axes with an appropriate scale and plot the points.

time after noon (hours) elevation (meters)
0 -567
1 -892
2 -1,606
3 -1,289
4 -990
5 -702
6 -365

### Problem 2

$$30 + \text-30 = 0$$.

1. Write another sum of two numbers that equals 0.
2. Write a sum of three numbers that equals 0.
3. Write a sum of four numbers that equals 0, none of which are opposites.

### Solution

(From Unit 7, Lesson 7.)

### Problem 3

The $$x$$-axis represents the number of hours before or after noon, and the $$y$$-axis represents the temperature in degrees Celsius.

1. At 9 a.m., it was below freezing. In what quadrant would this point be plotted?

2. At 11 a.m., it was $$10^\circ \text{C}$$. In what quadrant would this point be plotted?

3. Choose another time and temperature. Then tell the quadrant where the point should be plotted.

4. What does the point $$(0, 0)$$ represent in this context?

### Problem 4

Solve each equation.

$$3a = 12$$

$$b + 3.3 = 8.9$$

$$1 = \frac{1}{4} c$$

$$5\frac{1}{2} = d+ \frac{1}{4}$$

$$2e = 6.4$$

### Solution

(From Unit 4, Lesson 4.)

### Problem 5

Crater Lake in Oregon is shaped like a circle with a diameter of about 5.5 miles.

1. How far is it around the perimeter of Crater Lake?

2. What is the area of the surface of Crater Lake?

### Solution

(From Unit 5, Lesson 19.)

### Problem 6

A type of green paint is made by mixing 2 cups of yellow with 3.5 cups of blue.

1. Find a mixture that will make the same shade of green but a smaller amount.

2. Find a mixture that will make the same shade of green but a larger amount.

3. Find a mixture that will make a different shade of green that is bluer.

4. Find a mixture that will make a different shade of green that is more yellow.