ACT prep slides

Question 1

what is an irrational number?

Answer 1

a number that cannot be represented as an exact fraction

Question 2

If xy = 144, x + y = 30, and x > y, what is the value of x – y ?

Answer 2

18, x=24, y=6

Question 3

What is the slope of any line parallel to the line 9x + 4y = 7 ?

Answer 3

4y=-9x + 7
y=-9/4(x) +7/4
therefore, slope must be -9/4

Question 4

formula for circumference

Answer 4

2∏r^2

Question 5

Points A, B, C, and D are on a line such that B is between A and C, and C is between B and D. The distance from A to B is 6 units. The distance from B to C is twice the distance from A to B, and the distance from C to D is twice the distance from B to C. What is the distance, in units, from the midpoint of to the midpoint of ?

Answer 5

18

Question 6

area of a circle

Answer 6

pi(r^2)

Question 7

For all nonzero real numbers p, t, x, and y such that , which of the following expressions is equivalent to t ?

Answer 7

cross multiply, 2xt = 3py. Then dividing each side by 2x, you get t = 3py/2x

Question 8

Ms. Hernandez began her math class by saying:

I’m thinking of 5 numbers such that their mean is equal to their median. If 4 of the numbers are 14, 8, 16, and 14, what is the 5th number?

What is the 5th number Ms. Hernandez is thinking of?

Answer 8

solve for x,
(14+8+16+14+x)/5,
So, 14(5) = 52 + x, or x = 18.