Math 8
Unit 4 Study Guide
Sol 8.3, 8.8a Proportions, Percent, Discount, Tax, Tip, Dilation
Name ______________________
Date: _____________ Block ______
Solve questions 1-3 using the percent equation. Round to the nearest tenth, if needed. Show all work!!! (2 pts each)
1. 15 is 20% of what number?
2. 28 is what percent of 120?
3. Find 55% of 65.
4. Are the following triangles similar? Show All Work. (3pts)
For #5-12, Set up a percent equation (or proportion) (1pt). Solve each problem (1 pt). SHOW ALL WORK!!!
5. Find the sales tax percent (Hint: % of Change) if your
subtotal at Macy’s is $79.50 and ultimately cost
$106.21.
6. A store buys a perfume from a manufacturer for
$45.00 and marks it up 28%. What is the final price
of the perfume for the customer?
7. A $67 hockey ticket is on sale for $46.
a) Find the discount. (1 pt)
b) Find the Percent of Change. (1 pt)
8. Find the simple interest to the nearest cent on
$22,000 at 6% for 13 years.
9. Find the new balance of a savings account if $7,000
3
was deposited 3 4 years ago at 2.2% simple interest.
10. Suppose Sara invests $9,000 at an annual rate of
5.3%. How long will it take until Sara earns $1,908?
12. A mountain bike originally cost $499. The price was
marked up by 32%. The bike was later sold with
15% discount. What was the final sales price? Round
to the nearest cent.
11. What is the annual interest rate if $10,500 is
invested for 6 months and $244.38 in interest is
earned?
11) Amt of Markup __________ (1/2 pt)
Amt of Discount __________ (1/2 pt)
Final Price __________ (1 pt)
13. Record the following transactions on your check registry . (1 pt) Keep a running balance. Then answer the question at
the end of your transactions. (1 pt)
Check
Deposit Withdrawal
Date Transaction
Balance
a) On Sept 4, there is $800 in your
Number
(+)
(-)
checking account.
a.
Beginning
--9/4
$800.00
Balance
b) Thurs night, Sept 9, you are having
b.
a party and spend $65.80 on food
and drinks using check #455 at Wal- c.
Mart.
d.
c) On Saturday, Sept 11, you mow
your neighbor’s lawn for $30 and
e.
deposit the earnings into your
account.
d) On Sept 15, you pay for your mother’s gas in her car using your debit card. The total was $75.76.
e) It’s Sept 20, Mrs. Kayal’s birthday, you buy her a pack of lead pencils from Target that cost $5.99.
f)
What is the balance at the end of the day on Sept.20?
14. How tall is the flagpole?
__________________________
15. A car uses 32 gallons of gasoline to travel 820 miles. How many gallons are used to go 150 miles?
16. A $70 skateboard is on sale for 15% off. Which is a better deal: to add on 6% sales tax, then take the 15% discount, or
to take the discount off first, then add on the sales tax?
17. Bob took $100 to the hardware store with him. He bought an electric drill that cost $48.22, paint that cost $18.99 and
a toolbox for $23.98. The tool box was on 25% off sale. Did he have enough money after paying also a 6% tax?
18. Find the coordinates of the vertices of triangle A’B’C’ after triangle ABC is dilated using the given scale factor. Then
graph triangle ABC and its dilation.
A(–2, –2), B(–1, 2), C(2, 1); scale factor 2
19. Dilate the triangle below from the origin using a a scale factor of
1
. (3 pts.)
4
Know your vocabulary!!!
1. You can express a ________________ as a fraction by writing it as a fraction with a denominator of 100.
2. _________________ is the amount of money paid or earned for the use of money.
3. The amount of money invested or borrowed is called the ________________.
4. When the new amount is less than the original amount, the percent of change is called a(n) _______________.
5. The amount by which the regular price of an item is reduced is called the ______________ or _______________.
6. The amount the customer pays for an item is called the__________________________.
7. A store buys a television for $100. It then does a _________________ and sells it to the public for $250.
8. The average amount of snow that fell each hour over a period of several hours is an example of a ____________
Matching.
9. Total Value of an Investment
Percent of change is the percent that a __________________ increases or
decreases.
10. Total Cost of a loan
The _____________________________ is equal to the sum of the original cost
and the interest paid.
11. Percent of Change
Percent increase and percent decrease are both _______________________.
12. Quantity
The____________________________ is equal to the sum of the original
investment and the interest earned.
Know your formulas!!!
13. Rate of change:
14. Percent of change:
15. Percent equation:
16. Simple Interest
17. Find the rate of change of the line and interpret its meaning