TACTIC 15 : TRUST ALL GRIDS, GRAPHS, AND CHARTS

S.A.T. Math Testing Tactics

Trust all Grids, Graphs, and Charts.

In Tactic 2 (If a diagram is drawn to scale, trust it, then trust your eyes), we learned that on the S.A.T. test diagrams are drawn as accurately as possible.

Similarly, we can trust grids, bar graphs, line graphs, pie charts, tables, etc. to hold correct information that is represented visually as accurately as possible.

Percent Increase or Percent Decrease

Before you take the S.A.T. , you should learn (memorize if necessary!!!) how to find a percent increase or percent decrease.

Percent Change =

Example 15.1

From the picture you can determine:

• The area of the triangleA = ½ b h

• The length of each side distance =

•The perimeter of the triangle

•The slopes of each line segment

slope =

212

212 )()( yyxx

12

12

xx

yy

Example 15.2

At Central High School, 1000 students study exactly 1 foreign language each.

In this pie chart, you could estimate that

French students= approx. ¼ of 1000 or approx. 250 students

# Italian students = approx. # Latin students

# Spanish students = approx 1/3 of 1000 or approx. 333 students

Foreign Languages Studied By 1000 Students At Central High

School

SpanishFrench

LatinItalian

German

Example 15.3

From the graph, you could determine: The percent increase or percent

decrease between any two pairs of years.

The average number of wins per year The number of wins in any given

year.

Example: Find the Percent increase between

2001 and 2002

Change = (12 – 3) = 9% increase = (9 / 3) x 100 = 300%

2000 2001 2002 2003 20040

2

4

6

8

10

12

14

Number of Tournaments John Won By Year

In Conclusion

Remember:

You can IN GENERAL draw conclusions about grids, graphs, and charts simply by trusting your eyes and what you see.

Many times you can eliminate ABSURD answers on the S.A.T. just by doing a quick examination of the provided picture.