Solving and Rearranging Literal Equations for 8th Graders

1. A rectangle's area is given by the formula A = l * w, where A is the area, l is the length, and w is the width. If the area is 48 square units and the width is 4 units, what is the length?

• 12 units

• 8 units

• 10 units

• 6 units

2. The formula for the circumference of a circle is C = 2πr. If the circumference is 31.4 units, what is the radius r?

• 3.2

• 10.0

• 7.5

• 5.0

3. The formula for the volume of a cylinder is V = πr²h. If the volume is 100π cubic units and the height h is 5 units, what is the radius r?

• 3√5

• 4

• 2π

• 2√5

4. The equation for converting Celsius to Fahrenheit is F = (9/5)C + 32. If the temperature in Fahrenheit is 68 degrees, what is the temperature in Celsius C?

• 15

• 20

• 25

• 30

5. The formula for the perimeter of a triangle is P = a + b + c. If the perimeter is 30 units and the lengths of two sides are 10 units and 12 units, what is the length of the third side c?

• 20

• 8

• 15

• 6

6. The formula for the distance traveled is d = rt, where d is distance, r is rate, and t is time. If a car travels 150 miles at a rate of 50 miles per hour, how long did it take to travel that distance?

• 4 hours

• 3 hours

• 5 hours

• 2 hours

7. The formula for the area of a triangle is A = (1/2)bh. If the area is 24 square units and the base b is 8 units, what is the height h?

• 10

• 4

• 6

• 12

8. The formula for the simple interest is I = Prt, where I is interest, P is principal, r is rate, and t is time. If the interest earned is $120, the principal is $800, and the time is 2 years, what is the rate r?

• 12.5%

• 7.5%

• 10%

• 5%

9. The formula for the speed of an object is s = d/t, where s is speed, d is distance, and t is time. If a runner completes a 10 km race in 50 minutes, what is their speed in km/h?

• 8 km/h

• 15 km/h

• 12 km/h

• 10 km/h

10. The formula for the surface area of a sphere is SA = 4πr². If the surface area is 50π square units, what is the radius r of the sphere?

• 2.5√2

• 3π

• 4π

• 5π