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ACT formulas 2

different formulas used on the ACT off of EriktheRed tutoring

volume for a right cylinder pi x r^2 x h
area of a trapezoid (base_1 + base_2/2) x h base 1 is on the bottom, base 2 is on the top, the height is the dotted line with the right angle
Area for a rhombus if l=w lh
formula for the length of an arc (n^0/360^0) x 2 x pi x r
formula for the area of a sector of a circle (n^0/360^0) x pi x r^2
definition of similar triangles they have the same shape. The corresponding angles are equal, and the corresponding sides are in proportion. For example, the 3–4–5 triangle and the 6–8–10 triangle
the length of on side of a triangle is ALWAYS less that the sum and more than the difference of the lengths of the other two sides
for a special right triangle with 1 90 degree angle and 2 45 degree angles the hyp is x√2 and the legs are both x
parallel lines have equal slopes
perpendicular lines have negative reciprocal slopes : m_1 x m_2=-1
cosecant (csc) opposite of cosine; c/b or hypotenuse/adjacent
cotangent (cot) opposite of tangent; b/a or adjacent/opposite
secant (sec) opposite of sine; c/a or hypotenuse/opposie
how do you average evenly spaced numbers average the smallest and the largest. the average of all the integers between 13 and 77 is the same as the average of 13 and 77
how many degrees are on the outside of of a triangle? 360
rectangle a four sided figure with four right angles
parallelogram has two pairs of parallel sides
square a rectangle with 4 equal sides
trapezoid a quadrilateral with one pair of parallel sides and one pair of non parallel sides
how do you find the percent of increase or decrease? add or subtract the percent number to 100 percent and multiply it by the original number
to find the original whole before a percent set up an equation: think of 15%increase over x as 1.15x;
how do you find the combined percent increase and decrease? take the percents off or on to 100%
how to find part-to-part and whole-to-whole ratios put each number in the original ratio over the sum of numbers
average rate you combine the total distance and divide it by the total time
how do you find the sum from the average sum= average x number of terms
how do you find equations that are in terms of the other variables it means to isolate the one variable on one side of the equation
how to solve for absolute values take the equation and make two: one side equals to the positive answer and the other equals to a negative answer
when do you use a solid circle or an empty circle in graphing inequalities you use a solid circle if the point is included and an empty circle if the point is not included
equation for a circle in a graph with r as radius and centered at (h,k) (x-h)^2 + (y-k)^2=r^2
the form of an equation that makes a parabola y= ax^2 + bx + c
in a 5-12-13 triangle the sides are all in 5-12-13 ratios: if one side is 39 and another side is 36, then the final leg is 15
the sum of the measures of the interior angles of a polygon is (n-2)x180; n=number of sides
how to find one angle of a regular polygon divide the sum of the angles by the number of angles(which is the same as the number of sides
to find the interior angle of a polygon ((n-2)x180)/n
formula for the surface area of a rectangular solid 2lw + 2wh + 2lh
Created by: Teens