# Search Results for “euclid” ##### Euclid 1:47
Euclid's proof of the Pythagorean Theorem is illustrated.

Tags: Pythagoras, Pythagorean, Euclid ##### Euclids Elements - Book 1 - Proposition 01
The very first proposition, in which Euclid creates a equilateral triangle from a straight line by using two circles.

Tags: Euclid, Elements, Geometry, Equilateral, Triangle ##### Equilateral triangle construction
How Euclid constructs an equilateral triangle, using just a set of compasses.

Tags: equilateral, triangle, Euclid ##### Euclids Elements – Book 4 – Proposition 11
Can you create a regular pentagon without a protractor? Because it’s pretty impressive how Euclid did it with only a compass and a ruler. Note that the yellow triangle is similar to the one inside the pentagon.

Tags: Euclid, Elements, Geometry, Pentagon, Triangle ##### Euclids Elements – Book 3 – Proposition 08
This proposition proves that line AD is longest, ED is shorter, FD is shorter than ED, and CD is even shorter.and that for any line there is only one other line with a point on the circle and a point at D that is equal. (Unless you drag it to somewhere it's not supposed to be) I like it because it’s colorful.

Tags: Euclid, Elements, Geometry, Triangle ##### Euclids Elements - Book 3 - Proposition 14
Creating a tangent on a circle given point A that is outside the circle.

Tags: Euclid, Elements, Geometry, Circle, Tangent ##### Euclids Elements - Book 1 - Proposition 45
Creating a parallelogram equal to a given quadrilateral with a given angle.

Tags: Euclid, Elements, Geometry, Parallelogram, Triangle, Angle ##### Euclids Elements – Book 1 – Proposition 47
The famous Pythagorean Theorem. Can you see how it works?

Tags: Euclid, Elements, Geometry, Pythagorean, Theorem ##### Euclids Elements – Book 1 – Proposition 42
To construct, in a given rectilineal angle, a parallelogram equal to a given triangle. In other words, given angle D and triangle ABC (in blue), construct a parallelogram (in yellow) that has an equal area to triangle ABC.

Tags: Euclid, Elements, Geometry, Parallelogram, Triangle ##### Euclids Elements - Book 2 - Proposition 14
One of my favorite apps because it looks deceptively simple, but takes some really creative thinking. This app creates a square (in red) that has the same area as a given quadrilateral.

Tags: Euclid, Elements, Geometry, Square, Quadrilateral