8th STAAR 19/21 MM

Aquarium I contains 4.6 gallons of water. Louise will begin filling Aquarium I at a rate of

1.2 gallons per minute.

Aquarium II contains 54.6 gallons of water. Isaac will begin draining Aquarium II at a rate of

0.8 gallon per minute.

After how many minutes will both aquariums contain the same amount of water?

• 148 minutes

• 125 minutes

• 25 minutes

• 50 minutes

The width of a rectangle is 4 feet, and the diagonal length of the rectangle is 13 feet. Which

measurement is closest to the length of this rectangle in feet?

• 9 ft

• 52 ft

• 12.4 ft

• 13.6 ft

Mathematical Equivalence

ON

The side lengths of the base of a triangular prism are 5 meters, 8 meters, and 10 meters. The

height of the prism is 16.5 meters.

What is the lateral surface area of the prism in square meters?

Which table represents a non-proportional relationship between x and y?

• 
• 
• 
• 

A student’s parents invested $5,000 in a college savings account that pays 4.85% annual

simple interest. No additional deposits or withdrawals will be made.

Which amount is closest to the amount of money in the account at the end of 15 years?

• $5,174.11

• $10,174.11

• $3,637.50

• $8,637.50

Mathematical Equivalence

ON

The side lengths in yards of a triangle and a square are shown in the diagram.

The perimeter of the triangle is equal to the perimeter of the square. What is the value of x?

• -4

• 6