10 Math Formulas to Remember for the ACT

By Lisa Zimmer Hatch, Scott A. Hatch

If you’re in advanced math classes, chances are you’ve forgotten many of the foundational formulas needed for the ACT that you learned in grade school and middle school. You don’t have time to jog your memory on exam day, so take the time to commit the following ten formulas to memory now:

  • Average formula:

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  • Area of a triangle, where b is the base and h is the height:

    image1.png

  • Area of a rectangle, where l is the length and w is the width:

    A = lw

  • Area of a trapezoid, where b is each of the two bases and h is the height:

    image2.png

  • Volume of a rectangular solid, where l is the length, w is the width, and h is the height:

    V = lwh

  • Area of a circle, where r is the radius:

    image3.png

  • Circumference of a circle, where r is the radius:

    image4.png

  • Formula for finding the distance between points on the coordinate plane, where x is each of the two x-coordinates and y is each of the two y-coordinates:

    image5.png

  • Sum of series of numbers, where n = # of terms, a = 1st term, and d is difference between each of the terms:

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