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SAT Math Reference BoxThis is it: the Math section of the SAT®. You look at the first problem and instantly get stuck. Which formula were you supposed to use again? Skip. Next question: same thing! You flip back to the reference page but all the formulas start to run together and you draw a blank… That reference box is not as helpful as you thought. It’s one thing to know the formulas will be on the test, it’s another to actually know how to use them.  Not knowing when to use formulas can cause you more stress, take more time, and give you lower your chance to get that high score you want.  Let ME help you avoid all of that with this tip:  Learn how to use the formulas. It will save you time and give you confidence so you can breeze though the problems and finally take a breath. Practicing examples like the ones below will help you out.

 

Area of a circle: The area of a circle is the number of square units inside that circle.

The area of a circle is 78.5 square meters
What is the radius (r)?

Glittery circle

  A= πr2
  78.5 m2 = 3.14 · r · r
  78.5 m2 ÷ 3.14 = r · r
  25 m2 = r · r

  r = 5 m

 

Area of a rectangle: To find the area of a rectangle, multiply the length (l) by the width (w).

A rectangle has a length of 8 centimeters and a width of 3 centimeters. Find the area.

glittery 8x3 rectangle


  A= lw
  = (3 cm) · (8 cm) = 24 cm2

  A= 24 cm2

 

Pythagorean Theorem: In a right angled triangle: the square of the hypotenuse (the longest side) is equal to the sum of the squares of the other two sides.

 

 

Pythagorean Theorem

a2 + b2 = c2
92 + b2 = 152
81 + b2 = 225

Subtract 81 from both sides:

b2 = 144
b = √144

b = 12

Volume of a cylinder: A cylinder is a space figure having two congruent circular bases that are parallel.

 

Volume of cylinder

  Find the volume of a cylindrical canister with radius
  7 cm and height 12 cm

  V=πr2h
  V= 3.142 · 72 · 12
  V= 3.142 · 49 · 12

  V= 1847.5


 

It may make sense to take the easy way out by finding shortcuts, but sometimes shortcuts turn problems from simple to super complicated. Once you internalize how to use the formulas, you’ll do less flipping to the reference box and more skipping through the hallways celebrating your triumph!

-Breea Mitchell

 

 


Sites we love: MathGoodies.com, Mathsteacher.com

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