.Surely you’ve discovered that the figure below is clipped from a pentagon. Right? Yeh! let us focus within the border drawn with a crayon, that is, within triangle DAB. How many isosceles are there within it? (For the moment, ignore the smaller pentagram A’C’E’B’D’ and all the triangle formed by their intersections.) Let’s count it!…

# Geometry

Geometry is the brain gymnastic.

### Geometry, Junior Math (Gr 6 - 9), Math BASICS

# Protected: Regular Polygons and Perfect Circles – Defs & Principles

There is no excerpt because this is a protected post.

### Geometry, Math BASICS, Numbers

# Protected: The (3-4-5) Pattern for Pythagorean Triplets

There is no excerpt because this is a protected post.

### Geometry, Math BASICS, Numbers

# π Ideas (1) a Fun Way of Finding the π Value

#### This describes a fun way to find the π value.

It does not use any area calculation. Not even directly apply the Pythagorean Theorem. Basically it uses *the radius* as a *unit* to measure *the circumference* along the circle. But how can you measure a curve using a line segment, without getting into tech difficulties? There’s simple yet smart solutions. Read on, you can find that out!

### Geometry, Glossary

# Def: Diagonal of a Polygon

A diagonal is any segment that joins two vertices that are not adjacent to (next to) each other.

### Geometry, High School Math, Methods of Learning

# Protected: Circular Geometry and Thales’ Theorem

There is no excerpt because this is a protected post.

### Geometry, Math for Early Age /Elementary (G5 under)

# The symbol π — where does it come from?

Counting from the first relevant use, the symbol π has already had a history of more than 360 years!

Do you know who has used it first and who has made it popular?

### Geometry

# Length of Hypotenuse (3) and PT — the Pythagorean Theorem

This is the conclusion part on calculate the hypotenuse. We come to Pythagorean Theorem through own our effort!

### Geometry

# Hypotenuse of a Right Triangle — by Area Approach (2)

Continuing from Part one of this article. We look at the hypotenuse when the two legs are in 1:2.

### Geometry

# Ribbon Square is Fun

Have you ever tried to use ribbons crossing each other to enclose a square? And do it in a rectangle “something”, like a pool in fitness center?

Some questions are: What is the largest ‘ribbon square’ you can make? And the smallest? How many altogether?