Angles within a triangle can be expressed one of two ways. This can either be in degrees or radians. Therefore to convert between the two:
Stem and Leaf Plots Stem and leaf plot questions are a way of displaying a set of data in a concise manner. The name refers to the fact that the leading digit (usually the tens digit) is removed from each data point, and instead is used as a label for a row that includes all…
Translations Translation questions will involve moving a shape or the graph of a function in one of three ways: translation, rotation, or reflection. Translation Rotation Reflection
Compare numbers Some questions on the ACT math section might require comparing the size of numbers expressed in different forms, or where the expressions contain only variables. For these questions, it’s important to remember simple things about different expressions: Radicals/Square Roots: The equivalent/value of a square root gets large as the number under the root/radical gets…
System of equations with three equations Most systems of equations problems only involve two equations, but occasionally they’ll include three equations, often in the form of a word problem. For these problems, students need to isolate two different variables in two of the equations. These then need to be substituted in for each other in…
Lowest Common Denominator The Lowest Common Denominator is the smallest number that can be a denominator for two separate fractions. Another way to think of it is that it’s the smallest number that both original denominators can factor into. This is why the most common way to find the LCD is simply to multiply the…
Pythagorean Triplets There are a few common triangles that appear on the ACT math section that are called “Pythagorean Triplets”. These are right triangles where if a student knows two of the sides, they also can know the third side automatically without having to use the Pythagorean theorem. These triangles are known as 3,4,5 and…
Value/frequency charts Frequency charts summarize data sets by showing how often each data point appears within a set. This can be displayed as either a table or a graph. Questions about these charts will generally focus on the mean/median of the data set. Students should be comfortable calculating the mean/median from either of these two…
Use the radius Any time a circle appears in a problem, the first thing to think about is the radius of the circle. It is the core piece of information about the circle, and it is the thing that is most commonly used to calculate or infer information about things that appear in the rest…
Parallelogram Parallelograms are an important thing to review for the ACT, because they tend to be something students are less familiar or comfortable with. Problems involving parallelograms can therefore become an easy place for students to lose points. Some key things to remember about parallelograms are as follows. Adjacent Angles Area Formula The area of…