1. COLEGIO SAN PATRICIO
ANSWERS Math Practice for 2nd Period Exam
School Year 2010 – 2011
I.- The meaning of the Numbers: underline the correct answer
1.- 24.8 km is the same as: 24km 800 m
2.- 16.8 millions: 16 million 800 thousand
3.- 5.2 kg: 5 kg 200 g
II.-Tree Diagram.- Draw a tree diagram to answer the question .
4.- From the different kinds of pants customers can choose from 4 colors, 2
sizes, and either cotton or wool How many choices does a customer
have?
a) 16
* Answer the questions
5.- Find the total number of choices if only 5 colors are available: 20
III.- PROPORTIONS
6.- If Tina has studied 1 of the 14 pages she has to study for the period exam.
7
How many pages is she missing?
A= She is missing 12 pages.

2. 1 = 2 pages (she has studied)
7 14 pages (total number of pages) so, 14 -2= 12 pages are missing.
7.- If I have finished 3 of the 24 problems of the math homework, how many
4
am I missing?
A= I am missing 6 pages.
3 = 18 (problems done)
4 24 (total number of problems) so, 24 – 18 = 6 problems are missing.
8.- The new highway to Saltillo has 300 km. If only 0.5 km have light how many
meters are still missing?
A= First, I need to change the km to meters:
300 km = 300,000 meters
0.5 km = 500 meters
Then, you subtract the 500 meters from the 300,000 meters, and you get the answer
So, the answer is 299,500 meters
10.- To buy a box of brownies Mary put $21.00, Roxy $18.00 and Marion $24.00.
If there are 21 brownies in the box, how many brownies will each one get?
Mary Roxy Marion Total
$21.00 $18.00 $ 24.00 $ 63.00
7 brownies 6 brownies 8 brownies 21 brownies
You need to ask yourself, what am I giving out?, then you divide that by the other
total and you get the factor. After that, you just multiply each amount of money
that each gave by the factor.
21 ÷ 63= 0.33 (Factor)
11.- If 6 students got 18 donuts in a party, how many will 12 get?
6 students --- 18 donuts
12 students --- ? donuts
A= 12 students will get 36 donuts.
12.- If hotdogs are sold at $4.50 each. How much will 10 cost?

3. A= 10 hotdogs are sold for $45 pesos.
IV.- SCALE DRAWING
Original copy 1 copy2 copy 3 copy 4 copy 5
1.-SIDE A 4 8 2 1 16 2
2.-SIDE B 16 32 8 4 64 8
3.-SIDE C 5 10 2.5 1.25 20 2.5
4.-SIDE D 2 4 1 0.5 8 1
V.- GEOMETRY.-
Trace the following:
13.- A line segment
14. A line segment with its “Mediatriz”
15.- A 120º angle 16.- the “Bisectriz” of this angle
VI. ANGLES.
17. What is the central angle of a dodecagon?
A= To find the central angle you need to do the next procedure:
Divide 360° by the number of sides of the figure, in this case, 12 sides.

4. 360° ÷ 12 = 30°
So, the answer is 30°.
18.What is the interior angle of an “undecagon”?
A= To find the interior angle you need to:
First, find the central angle of the figure---
360° ÷11= 32.7° (notice, that I am just leaving one number after the decimal point).
Then, you need to subtract the central angle to 180°---
180° ― 32.7° = 147.3°
So, the answer is 147.3°
Complete the following sentences:
19.- A line that has ending points: Line Segment
20.- The sum of the measures of each side: Perimeter
21.- The symmetry line of a line segment: “Mediatriz”
22.- The line that goes from the center of the regular polygon to the center of
one of its sides: “Apotema”
23.- The line that divides an angle into two equal angles: “Bisectriz”