8th Grade Math Prompt

1
8th Grade Math Prompt 3

• Jada has a choice of two health clubs FitZone
  and the Ab shack. At FitZone, there is a one
  time membership fee of 100 plus 2 per visit.
  At the Ab shack, there is a charge of 7 per
  visit and no membership fee. Write an equation
  to find the cost of each health club based on the
  number of times (n), Jada would visit.
• Which is the better deal if Jada only
  goes once a week?
• (52 times a year)

2

• FitZone
• Think.. The number of times (n) x 2
  membership fee cost
• So 2n 100
  cost
• charge per visit number of visits
  membership fee

3

• Ab shack
• Think The number of times (n) x 7 cost
• So 7n cost
• charge per visit number of
  visits

4

• Which is the better deal?
• Work out each equation.
• 2n 100 cost at FitZone
• 2 (52) 100
• 104 100
• 204 cost at FitZone
• 7n cost at Ab shack
• 7 (52)
• 364 cost at Ab shack
• FitZone is the better deal even though you pay a
  membership fee!

5

• Grading was as follows
• 3 points both equations correct answer
  correct
• 2 points two correct from above
• (1 equation correct answer)
• (2 equations wrong answer)
• 1 point - one correct from above
• (equations
  answer)
• (1 equation wrong answer)
• (wrong equations correct answer)
• 0 points - no correct answers

6

• Scientists have discovered life on Mars! They
  are tiny creatures born with a head and 2 feet.
  Each month they grow 2 new body segments each
  with 2 legs. Does the graph below represent the
  growth for this creature? EXPLAIN Why or Why
  Not.
• Growth of Creature
• 70
• 60
• 50
• Number of legs 40
• 30
• 20
• 10
• 0 1 2 3 4 5 6 7 8
• Month

• Month Number of legs
• 0 2
• 4
• 6
• 8
• 10
• 12
• 14

What is the equation for this line?
7

• Answer NO! The graph and the problem do not
  match. The creature is born with a head and 2
  feet. It grows 2 new body segments each with 2
  legs every month. So after the first month it
  should have 6 legs (2 from when born 2 for each
  body segment) (2 4 6 after the first month)
• HINT READ the problem carefully! Never assume
  the graph is correct. Always check if the data
  matches the situation.

8

• What is the equation of this line?
• Look at the table.
• X increases by
  1
• Y increases by
  2
• The y-intercept is 2 on the graph
• So the slope is y / x or 2 / 1 2
• The equation is y 2x 2 for this
  situation.

9

• Grading was as follows
• 3 points correct answer,
• explanation equation
• 2 points two correct from above
• 1 point - one correct from above
• 0 Points no correct answers

10

• 3. Triangle ABC is a right triangle with sides AB
  5 and BC 8. What is the length of the
  hypotenuse?
• A
• B
  C

11

• Use the Pythagorean Theorem.
• a2 b2 c2
• Name one of the legs a, and the other leg b.
  Remember the hypotenuse is always c.
• Well say side AB is leg a and side BC is leg b.

12

• Use the formula.
• a2 b2 c2
• 52 82 c2
• 25 64 c2
• 89 c2
• v89 c
• 9.4 c

13

• Grading was as follows
• 2 points correct answer process
• 1 point - one correct from above
• 0 Points no correct answer / process