Mathematical Relationships and Functions STAAR 8th Grade Review

What is the formula for the slope-intercept form of a linear equation?

• y = mx + b

• y = kx

• m = (y2 - y1) / (x2 - x1)

• C = 2πr

How do you calculate the circumference of a circle using the diameter?

• C = 2πr

• C = πd

• A = 1/2bh

What is the formula for the area of a triangle?

• A = bh

• A = 1/2bh

• A = 1/3Bh

Which formula represents the Pythagorean theorem?

• I = Prt

What is the formula for the volume of a sphere?

• V = Bh

• V = 1/3Bh

• S = 2πrh

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.

What value of x makes this equation true? 0.17x – 0.03 = 0.03x – 0.002

• x = 0.2

• x = 0.1

• x = 0.25

• x = 0.15

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

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

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

• 9 m, 11 m, 13 m

• 18 m, 24 m, 30 m

• 7 m, 24 m, 25 m

• 20 m, 21 m, 29 m