40 Question Mock NEW STAAR (MATH8)

Triangle 1 is dilated by a scale factor of 4.1 using the origin as the center of dilation to create Triangle 2. Which statement about the area and perimeter of Triangle 2 is true?

• The perimeter is 4.1 times the perimeter of Triangle 1, and the area is 4.1 times the area of Triangle 1.

• The perimeter is 8.2 times the perimeter of Triangle 1, and the area is 8.2 times the area of Triangle 1.

• The perimeter is 4.1 times the perimeter of Triangle 1, and the area is 16.81 times the area of Triangle 1.

• The perimeter is 16.4 times the perimeter of Triangle 1, and the area is 16.81 times the area of Triangle 1.

Tags

8.10.D

Mathematical Equivalence

ON

Answer explanation

Tags

8.8.C

A family has a hot dog cookout every year. The scatterplot shows the number of people who have attended each cookout and the number of hot dogs that were eaten each year.

This year 45 people are expected to attend the cookout. Based on the scatterplot, about how many hot dogs should the family prepare?

• 83

• 52

• 36

• 40

Answer explanation

Draw a straight line on Patty Paper and place it over the graph so that it is in the middle of the points - equal points above the trend line as below the trend line.

Extend out the x-axis to 45 go up to the trend line, stop, and go over to the y-axis for answer.

Tags

8.5.D

A gas company charges a $16 monthly service fee and $0.6924 per hundred cubic feet of natural gas used during a month. Which equation best represents y, the gas company's monthly charges in dollars for using x hundred cubic feet of natural gas?

• y = 0.6924x – 16

• y = 16x + 0.6924

• y = 16x – 0.6924

• y = 0.6924x + 16

Answer explanation

Equation needs to be in slope-intercept form.

"m" is the slope/rate - look for key words like each, every, per, or percent.

"b" is the y-intercept/starting amount - look for words like fee, shipping, or extra.

Tags

8.5.I

Which set of side length measurements in meters does NOT make a right triangle?

• 9 m 11 m 13 m

• 18 m 24 m 25 m

• 7 m 24 m 25 m

• 20 m 21m 29 m

Tags

8.7.C

A faucet leaks 0.8 gallon of water every 2 hours.

Which graph has a slope that best represents the number of gallons per hour leakes by the faucet?

• 
• 
• 
• 

Answer explanation

Notice the labels on the x-axis and y-axis.

Find the graph that has a point at x = 2 hours and y = 0.8 gallons.

Tags

8.4.B

A poster storage tube in the shape of a cylinder has a diameter of 3.5 inches and a volume of 122.5π cubic inches.

What is the height of the poster storage tube in inches?

Mathematical Equivalence

ON

Answer explanation

Tags

8.7.A

Which graph represents y as a function of x?

• 
• 
• 
• 

Answer explanation

Use the vertical line test to see if x-value repeats. If it crosses a vertical line more than 1 time, then NOT a function.

Tags

8.5.G

A triangular prism and its dimensions in centimeters are shown in the diagram.

What is the total surface area of the prism in square centimeter?

• 720 cm²

• 600 cm²

• 460 cm²

• 520 cm²

Tags

8.7.B

The total annual cost to attend a community college is $4,000. The college offered a high school senior a scholarship for $1,500 but will need to earn enough to pay the remaining cost. It is 5 months until the remaining cost must be paid.

What is the minimum amount the students need to earn per month to save enough money to pay the remaining cost?

• $300

• $600

• $500

• $800

Answer explanation

Subtract all the money that is given to help the student pay for college.

Then divide by the total number of months available to save.

Tags

8.12.G