Degree To Radian (or reverse)

How to convert from degree to radian or radian to degree?   

Using calculator:

→ What is 225 degree in radian?

We know that π = 180 degree so what we could do is using cross multiply:


How to convert from degree to radian or radian to degree?   

Without using a calculator:

30 degree = π/6 radian

Proof: π = 180 degree

180/6 = 30

60 degree = π/3 radian

Proof: π = 180 degree

180/3 = 60

90 degree = π/2 radian

Proof: π = 180 degree

180/2 = 90

45 degree = π/4 radian

Proof: π = 180 degree

180/4 = 45

These are the different degrees of special right triangle and we can use them to determine the measure of triangles, in radian, without the use of calculator.  

30-60-90 triangle

45-45-90 triangle



In math class there are 16 students. The topics that we are learning this year are quadratic, geometry, and algebraic fraction. After every lesson or chapter we have learned, we always have an assessment on it. There is one website that we can practice math online, Khan Academy. It is a very useful tool to help us learn better independently and/or with facilitator. 

As part of our learning, every single student got one calculator each from Liger, it calls Texas instrument. This calculator help us a lot in our learning, since it got so many functions that would provide efficiency while we are doing our math.

  • This is the textbook that we are using.

On the 14th October, 2017, everyone at Liger have took their first PSAT, just the practice one, so that we know how it looks like as well as our score, so that we know what we need to improve. Everyone did great, and we got about 2-3 more years to get ourselves prepare and work on what is needed before the real PSAT for college.