directed line segment 100 videos

ACT Science Section
ACT ACT Science
Short, helpful video on ACT Science section by top ACT prep instructor, Devorah. Videos are produced by leading online education provider, Brightstorm.
Science section overview directions format pacing 
Special Isosceles Triangle Properties
Geometry Triangles
How to identify a segment from the vertex angle in an isosceles triangle to the opposite side.
isosceles triangle angle bisector altitude median 
Navigation Problems
Precalculus Vectors and Parametric Equations
How we measure airspeed, wind, groundspeed, and other variables in navigation.
navigation airplane flight airspeed heading groundspeed course wind speed wind direction vector addition magnitude direction 
Definitions and Applications of Absolute Value
Algebra Absolute Value
What is absolute value?
absolute value number line distance 
Rays
Geometry Geometry Building Blocks
How to identify, define, and label rays and opposite rays.
ray line endpoint opposite rays 
Finding the Slope of a Line from 2 Points
Algebra Linear Equations and Their Graphs
How to find the slope if you're given 2 points.
slope point ratio 
PointSlope Form of Linear Equations
Algebra Linear Equations and Their Graphs
How to write the equation of a line in pointslope form.
slope equation 
Comparing Fractions
PreAlgebra Fractions and MIxed Numbers
Comparing fractions using < or > and ordering them on the number line

Addition and Subtraction with Decimals
PreAlgebra Decimals and Percents
Adding or subtracting decimals by vertically lining up the zeros

Graphing One Variable Inequalities
PreAlgebra Solving Equations and Inequalities
Graphing one variable inequalities on a number line

Constructing Altitudes
Geometry Constructions
How to define an altitude and draw them on acute, right, and obtuse triangles.
altitudes perpendicular segment vertex opposite side obtuse acute right triangles 
Constructing the Centroid
Geometry Constructions
How to identify the centroid and the way it divides each of the medians.
point of concurrency center of mass center of gravity centroid proportional segments construct 
Alternate Interior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define alternate interior angles and their special properties.
parallel lines angles congruence interior transversal 
Alternate Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define alternate exterior angles and their special properties.
parallel lines angles congruence exterior transversal 
Same Side Interior and Same Side Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to describe same side interior and same side exterior angles and their special properties.
parallel lines angles congruence interior exterior transversal 
Constructing an Angle Bisector
Geometry Constructions
How to define and construct an angle bisector.
construction perpendicular equidistant shortest distance to a line bisector 
The Definition of the Derivative
Calculus The Derivative
How to define the derivative of a function at a point x=a.
average rate of change slope secant line instantaneous rate of change tangent line limits derivative difference quotient