Basic Geometry Topics

This is where it all begins: basic shapes, lines, and angles. Read on and let us take you on a magical geometry tour... NameDescriptionExamplePointA single location.Usually drawn as a dot.It...

Not to be confused with angels, angles are the pointed corners of shapes. Angles can be named three different ways. This angle could be named any of these ways: (counterclockwise) (cl...

A transversal is a line, or line segment, that intersects two or more other lines, or line segments. When a transversal intersects parallel lines, many angles are congruent. Let's take a peek...

A polygon is any closed figure with three or more straight sides. "Closed" means that there are no gaping holes in it and that all sides connect together. These Are Polygons:These Are Not Polyg...

Triangles are three-sided polygons, but we're sure that you already knew that. The triangle is the most sturdy of polygons. Its strong shape has been used to build buildings and bridges since th...

Quadrilaterals are four sided shapes. The most common include squares and rectangles, but there are loads of others as well. Like triangles, they are classified by their angles and sides.In this se...

As we discussed before, the three angles of a triangle always add up to 180°.In each case . By the way, means "the measurement of angle A."To find the total number of degrees in any polyg...

A circle is the set of all points equal in distance from a center point. If you pinned a piece of yarn down, then tied a pencil to the other end of the yarn and pulled the pencil around, you'd r...

Similar figures are always the same shape, but not the same size. They have equal angles but not equal side lengths. Check out a big square and a small square. They're both squares because they hav...

Congruent figures have the same shape and size, they're totally equal. Same-same. All of the sides on one figure are equal to all of the corresponding side on the other figure, and all of the angle...

The perimeter of a shape is the distance around the outside of the figure. It's pretty simple; just add up the lengths of each side.Perimeter is often used to find the measurements needed to put...

Area is the amount of space inside a two-dimensional shape. If you think about the floor of your bedroom, the area would be the maximum amount of floor you could throw your stuff on before you c...

Let's go over these area formulas one more time.Area of a Rectangle = Base × HeightArea of a Square = Base × HeightArea of a Square = s2A square, technically speaking, is a rectangle (don't remin...

In real life figures are often irregular shapes - a little bit messy. Think of your messy bedroom once more ‐ is it a perfect rectangle? The trick: break these figures into shapes that you kno...

Three‐dimensional objects are the solid shapes you see every day, like boxes, balls, coffee cups, and cans. Here are some helpful vocabulary terms for solids:Face: a flat side of a 3‐di...

The volume of a solid is the amount of space inside the object. It's how much water fits inside a bathtub, how much sand fills a bucket, or how much soda your friend can chug and hold in his stomac...

The formula for the volume of pyramids and cones tells you how much space is inside each object.For these two solid shapes, the volume formula is the same: it's one-third of the area of the ba...

A ball is a sphere. A sphere is a 3-D shape. 3-D shapes have volume. So a ball has volume. What it doesn't have is a base. So our tried and true formula for volume: Base × height, or Bh, doesn't w...

Surface Area of a Cone = πr2 + πrsTo find the surface area of a cone, we need to find the area of the circular base and the area of the curved section. This one involves a new measurement, s, whi...

A long time ago, in ancient Greece, a brilliant guy named Pythagoras discovered something pretty amazing and useful. Pythagorean Theorem: a2 + b2 = c2In a right triangle, the sum of the sq...