Geometry Help
Geometry is about the shape and size of things. It is the study of points, lines, angles, shapes, their relationships, and their properties.
Geometry Practice Questions
Free SAT Practice Questions (with Hints & Solutions) -
Geometry: Questions 1-5, Questions 6-10
Geometry Word Problems
Introduction
Basic Geometry Terms
Points, Lines, Line Segments, Midpoints, Rays, Planes, Space
Pairs of Lines
Intersecting Lines, Parallel Lines, Perpendicular Lines, Skew Lines
Angles
Angles
Naming an Angle (includes video), Measuring an Angle, Angles Around a Point
Types of Angles
Right Angles (includes video), 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
Right Triangles, Acute Triangles, ObtuseTtriangles,
Equilateral Triangles, Isosceles Triangles, Scalene Triangles
Special Right Triangles
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
Similar Triangles (includes video)
AA rule, RAR rule
Triangle Inequality (includes video)
Triangle Inequality Theorem, Angle-Side Relationship
Interior Angles of a Triangle (includes video)
Exterior 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
Areas of Polygons
Squares, Rectangles, (includes video)
Parallelograms, (includes video)
Triangle, (includes video)
Rhombus, (includes video)
Trapezoids (includes video)
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
Angles in a Circle
Quadrilaterals in a Circle
Angles and Intercepted Arcs (includes video)
Solid Geometry
Volume of Solids
Cubes, Rectangular Solids, (includes video)
Prisms, Cylinders, (includes video)
Spheres, Cones,
Pyramids, Nets of Solids
Surface Area of Solids (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
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)
Geometric Construction
Geometric Construction
Construct a Perpendicular Bisector (includes video)
Construct a Perpendicular Line through a Point (includes video)
Construct a 60° Angle by Constructing An Equilateral Triangle (includes video)
Construct An Angle Bisector (includes video)
Contruct Various Angles & Shapes : 30°, 45 °, 90°, 120°; hexagon, triangle (includes video)
Construct A Triangle Given The Length Of Its Three Sides
Construct A Triangle Given One Side And Two Angles
Construct A Triangle Given Two Sides And An Angle
Geometry Transformation
Geometry / Math Tranformation (includes video)
- Translation involves "sliding" the object from one position to another.
- Reflection involves "flipping" the object over a line called the line of reflection.
- Rotation involves "turning" 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).
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