Geometry Help

Looking for some Geometry Help? Our materials here review the basic terms and concepts in geometry and provide further lessons to help you develop your understanding of geometry and its applications to solving problems in real life.

Geometry is about the shape and size of things. It is the study of points, lines, angles, shapes, their relationships, and their properties.

 

Geometry Topics

Introduction

Basic Geometry Terms (includes video)
    Points, Lines, Line Segments, Midpoints, Rays, Planes, Space

Pairs of Lines (includes video)
    Intersecting Lines, Parallel Lines, Perpendicular Lines, Skew Lines


Angles

Naming an Angle, Angles Around a Point (includes video)

Measuring Angles Using a Protractor (includes video)

Drawing Angles Using a Protractor (includes video)
Types of Angles (includes video)
    Right Angles, Acute Angles, Obtuse Angles, Straight Angles 

Pairs of Angles 
    Complementary Angles, (includes video)
    Supplementary Angles, (includes video)
    Vertical Angles, (includes video)
    Corresponding Angles, (includes video)
    Alternate Interior Angles, Alternate Exterior Angles (includes video)

"Find the angle" problems (includes video)

 

Triangles

Types of Triangles (includes video)
    Right Triangles, Acute Triangles, Obtuse Ttriangles, (includes video)
    Equilateral Triangles, Isosceles Triangles, Scalene Triangles (includes video)

Special Right Triangles (includes video)
    3-4-5 Triangles, (includes video)
    45¡-45¡-90¡ Triangles, (includes video)
    30¡-60¡-90¡ Triangles (includes video)

Pythagorean Theorem (includes video)

Pythagorean Triples (includes video)

Pythagorean Theorem Word Problems (includes video)

Converse of the Pythagorean Theorem (includes video)

Congruent Triangles SSS rule, SAS rule, ASA rule, AAS rule (includes video) Hypotenuse Leg (HL) (includes video)

Similar Triangles (includes video)
    AA rule, RAR rule 

Triangle Inequality (includes video)
    Triangle Inequality Theorem, Angle-Side Relationship

Triangle Sum Theorem (includes video)

Exterior Angle Theorem (includes video)

Interior Angles of a Triangle (includes video)

Exterior Angles of a Triangle (includes video)

Angles of a Triangle (includes video)


Polygons

Quadrilaterals (includes video)
    Parallelograms, Rhombus, Rectangles, Squares, Trapezoids 

Types of Polygons (includes video)

Angles in Polygons (includes video)
    Sum of Angles in a Triangle, Dividing Polygons into Triangles, 
    Formula for Sum of Interior and Exterior Angles

Area of Polygons

Areas of Polygons 
    Squares, Rectangles, (includes video)
    Parallelograms, (includes video)
    Triangle, (includes video)
    Rhombus, (includes video)
    Trapezoids (includes video)

Perimeter of Polygons

Perimeters of Polygons (includes video)
    Squares, Rectangles, Parallelograms, Triangle, Rhombus, Trapezoids

 Circles

Circles 
    Diameter, Radius, Arc, Tangent, (includes video)
    Circumference of circle, (includes video)
    Area of circle (includes video)
    Length of arc in a circle, (includes video)
    Area of sector, (includes video)

Tangent to a Circle (includes video)Finding angles involving Tangents and Circles (includes video)

Degrees and Radians (includes video)


Circle Theorems

Chords of a Circle (includes video)

The Arrow Theorem (includes video)
The Bow Theorem (includes video)
"90 Degrees in Semicircle" Theorem (includes video)
Alternate Segment Theorem (includes video)Quadrilaterals in a Circle (includes video)Angles in a Circle (includes video)
Angles and Intercepted Arcs (includes video)

Solid Geometry

Volume of Solids
    Volume of Cubes (includes video)
    Volume of Rectangular Prisms (includes video)
    Volume of Prisms (includes video)
    Volume of Cylinders (includes video)
    Volume of Spheres (includes video)
    Volume of Cones, (includes video)
    Volume of Pyramids (includes video)

Surface Area of a Cube (includes video)
Surface Area of a Prism (includes video)
Surface Area of a Cylinder (includes video)
Surface Area of a Cone (includes video)
Surface Area of a Sphere (includes video)
Surface Area of a Pyramid (includes video)
    Surface Area of Solids (includes video)

Geometry Nets (includes video)


Geometrical Formulas

Summary of shapes and formulas (includes video)

 Area Formula of rectangle, parallelogram. rhombus, triangle, regular polygon, trapezium, and circle

Surface Area Formula of sphere, closed cylinder, hollow cylinder, cone and pyramid

Volume Formula of solid cylinder, hollow cylinder, prism, cone, pyramid, and sphere

 Coordinate Geometry and Graphs

Coordinate Geometry 
    Coordinate Plane, (includes video)

    Slopes, y-intercept, Negative Slope, (includes video)

    Equation of a Line, (includes video)

    Graphing Linear Equations (includes video)

    Slope and Intercept of a Linear Equation (includes video)

    Equation of a Line Parallel to the X-axis or Y-axis (includes video)

    Equation of a Line Given Its Slope and a Point on the Line (includes video)

    Equation of a Line Given Two Points on the Line (includes video)

    Slopes of Parallel Lines, Slopes of Perpendicular Lines, (includes video)

    Midpoint Formula (includes video)

     Distance Formula (includes video)


Graphing Inequalities (includes video)

Linear Programming (includes video)

Graphing Quadratic Functions (includes video)

Graphical Solutions of Quadratic Functions (includes video)

Graphing Cubic Functions (includes video)

Graphing Exponential Functions (includes video)

Graphing Reciprocal Functions

Sketching the Graphs of some Functions (includes video)

 

Geometric Construction 

Geometric Construction

Construct and Copy Lines (includes video)

Construct a Perpendicular Bisector (includes video)

Construct a Perpendicular Line through a Point (includes video)

Construct Parallel Lines (includes video)

Construct a 60¡ Angle by Constructing An Equilateral Triangle (includes video) 

Construct An Angle Bisector (includes video)

Construct A 30 Degree Angle (includes video)

Construct A 45 Degree Angle (includes video)

Construct A Triangle Given The Length Of Its Three Sides (SSS) (includes video) 

Construct A Triangle Given One Side And Two Angles (includes video) 

Construct A Triangle Given Two Sides And An Angle

Construct a Parallelogram and a Square (includes video)

Contruct Various Angles & Shapes : 30¡, 45 ¡, 90¡, 120¡; hexagon, triangle (includes video)

Locus of a Moving Point

 

Geometry Transformation

Geometry / Math Tranformation (includes video)

0.      Translation involves ÒslidingÓ the object from one position to another.

0.      Reflection involves ÒflippingÓ the object over a line called the line of reflection.

0.      Rotation involves ÒturningÓ the object about a point called the center of rotation.

 .      Dilation involves a resizing of the object. It could result in an increase in size (enlargement) or a decrease in size (reduction).