right angle

Home/Tag: right angle
29 07, 2017

Sine waves – trigonometry – math

By |2017-07-29T17:59:39-07:00July 29th, 2017|Math|0 Comments

Sine wave In order to save energy, many, many things in nature move in a kind of repeated pattern we call a sine wave: water waves, sound waves, light waves, electricity, radio waves, and microwaves, for instance. The waves move in one direction quickly, then slow down until they stop, and begin moving [...]

29 07, 2017

Cosine – Trigonometry – Math

By |2019-04-26T10:01:02-07:00July 29th, 2017|Math|0 Comments

Right triangle and cosine What is a cosine? A cosine, like a sine, is a mathematical way of thinking about a kind of movement that happens in nature. A cosine is really just a rephrasing of the same information we already had for calculating the sine function. What's a sine? More trigonometry History of astronomy [...]

29 07, 2017

What is a triangle? Simple geometry

By |2017-07-29T13:19:10-07:00July 29th, 2017|Math|0 Comments

This is an equilateral triangle. A triangle is any set of three points on a plane and the lines connecting those points to each other, as long as the three points aren't all on the same line (that would just be a line). Or, you could think of a triangle as the part of the plane that lies [...]

29 07, 2017

What is a trapezoid? Simple geometry

By |2017-07-29T13:16:13-07:00July 29th, 2017|Math|0 Comments

This is a trapezoid. A trapezoid is a kind of quadrilateral that has at least two sides that are parallel to each other. A parallelogram is a trapezoid that has two pairs of parallel sides, and a rhombus is a special kind of parallelogram, and so are rectangles and squares. To figure out the perimeter of a trapezoid, you can add the lengths of [...]

29 07, 2017

What is a square? Simple geometry

By |2018-04-23T16:01:49-07:00July 29th, 2017|Math|0 Comments

This is a square. The darker purple line is the perimeter of the square. A square is a flat shape, in one plane, defined by four points at the four corners. A square has four sides all of equal length, and four corners, all right angles (90 degree angles). So a square is a kind of rectangle. To figure [...]

29 07, 2017

Right triangle – Simple geometry

By |2017-07-29T13:00:51-07:00July 29th, 2017|Math|0 Comments

This is a right triangle, because one of the angles is a right angle. A right triangle is any triangle where one of the angles is exactly 90 degrees, or a right angle. You can't have more than one 90 degree angle in a triangle, or it would be a rectangle. In a right triangle, the side opposite [...]

29 07, 2017

Rectangle – area and perimeter

By |2018-04-23T16:01:22-07:00July 29th, 2017|Math|0 Comments

This is a rectangle. A rectangle is a flat shape, in one plane. It's defined by four points at the four corners. A rectangle has two sides of equal length opposite each other, and two other sides of equal length opposite each other, and four corners, all right angles (90 degree angles). A square is a special kind of rectangle. [...]

29 07, 2017

What is a quadrilateral? Squares and rectangles

By |2017-07-29T12:01:49-07:00July 29th, 2017|Math|0 Comments

This is a quadrilateral. A quadrilateral is a flat shape, in one plane, defined by four points at the four corners. A quadrilateral has four sides. The sides can be of any length. And it has four corners. They can be at any angle  to each other so long as they add up to 360 degrees. A rectangle is [...]

29 07, 2017

Perpendicular lines – Simple geometry

By |2017-07-29T11:41:47-07:00July 29th, 2017|Math|2 Comments

Perpendicular lines Two lines are perpendicular if they cross at right angles. You can test this by extending the lines until they cross (if they do not cross then they are parallel). Where the two lines cross, draw a right triangle, and then see whether the triangle conforms to the Pythagorean Theorem - if so, then your lines are crossing [...]