Hi everyone!

As a promise from my previous post, I am now beginning to post the Calculator Techniques I learned during my review before taking the Board Exam for Electronics Engineers!
Board Examination tests your knowledge on your chosen field after a bloody war on your college life and if you pass, you get your license as a reward. And regarding with the Board Exam I took, there were 4 major subjects to be taken and Math is the mood-setter of the whole exam because it the first subject to be battling with; it is a 4-hour exam with 100 items, which gives us 2.4 minutes (2 minutes and 24 seconds) to read, understand and answer 1 question. I find it difficult at first but when calculator techniques were discussed during the review, I practiced it since then and it really helped me during the actual exam. As our instructors told us, Math must be practiced not studied.

Today, I'll be discussing about a simple calculator technique in;

Trigonometry (Measuring Angles): Degree – Radian – Gradian Conversion

Degree - a unit of angle measurement, one three-hundred-and-sixtieth ( 1/360 ) of the circumference of a circle.source
Radian - a unit of angle measurement, equal to an angle at the center of a circle whose arc is equal in length to the radius.source

Gradian - *a unit of angle measurement in which the angle of an entire circle is 400 gradians, it is sometimes also called a gon or a grade.source

The ratio of the angle measurement is;

1 degree = π⁄180 radian = 10⁄9 gradian

With the ratio of measurements we can now try to answer some problems.

 Convert 20° to its equivalent radian and gradian values.

Using manual solution;

20 degrees to radian
20 degrees x ((π/180 radian)/1 degree) = π/9 radians

20 degrees to gradian
20 degrees x ((10/9 gradian)/1 degree) = 200/9 gradians

    Convert (5π)/3 radians to its equivalent degree and gradian values.

Using manual solution;

(5π)/3 radians to degree
(5π)/3 radians x (1degree/(π/180 radian)) = 300 degrees

(5π)/3 radian to gradian
(5π)/3 radians x (10/9 gradians /(π/180 radian)) = 1000/3 gradian

        Convert 450 gradians to its equivalent degree and radian values.

Using manual solution;

450 gradian to degree
450 gradians x (1 degree/(10/9 gradian)) = 405 degrees

450 gradian to radian
450 gradians x ((π/180 radian)/ (10/9 gradian)) = 9π/4 radians

Manual solution seems to be too long; it takes much time in pressing the buttons, yet in every problem in the board exam costs 2.4 minutes only.

Now I’ll be discussing a calculator technique that will surely save your time in answering the problem; less buttons to be pressed and less equation to input in your calculator screen. Let us answer the problems above using calculator technique.

We have to use a calculator function, press| Shift | |Ans| to properly assign the unit of the angle.

Press:|1| for degrees, |2| for radian, |3| for gradian.

Convert 20° to its equivalent radian and gradian values.

Using calcu tech;

20° to radian
20°/(1^r) = π/9 radians

Press the buttons in sequence;
|2| |0| |Shift| |Ans| |1| |⁌/⁌| |1| | Shift | |Ans| |2| |=|

Or set the mode of the calculator to radian
Then,
|Shift| |Mode| |4|

Press the buttons in sequence;
|2| |0| |Shift| |Ans| |1| |=|

20° to gradian
20°/(1^g) = 200/9 gradians

Press the buttons in sequence;
|2| |0| |Shift| |Ans| |1| |⁌/⁌| |1| | Shift | |Ans| |3| |=|

Or set the calculator to gradian
Press the buttons in sequence;
|Shift| |Mode| |5|

Then,
|2| |0| |Shift| |Ans| |1| |=|

Convert (5π)/3 radians to its equivalent degree and gradian values.

Using calcu tech;

(5π)/3 radians to degree
((5π)/3 r)/1° = 300°

Press the buttons in sequence;
|5| |Shift| |x10| |⁌/⁌| |3| |→| |Shift| |Ans| |2| |⁌/⁌| |1| |Shift| |Ans| |1| |=|

Or set the calculator to degree mode.
Press the buttons in sequence;
|Shift| |Mode| |3|

Then,
|5| |Shift| |x10| |⁌/⁌| |3| |→| |Shift| |Ans| |2| |=|

(5π)/3 radian to gradian
((5π)/3 r)/(1^g)= 1000/3 gradian

Press the buttons in sequence;
|5| |Shift| |x10| |⁌/⁌| |3| |→| |Shift| |Ans| |2| |⁌/⁌| |1| |Shift| |Ans| |3| |=|

Or set the calculator to gradian
Press the buttons in sequence;
|Shift| |Mode| |5|

Then,
|5| |Shift| |x10| |⁌/⁌| |3| |→| |Shift| |Ans| |2| |=|

Convert 450 gradians to its equivalent degree and radian values.

Using calculator technique;

450 gradians to degree
450^g/1° = 405°

Press the buttons in sequence;
|4| |5| |0| |Shift| |Ans| |3| |⁌/⁌| |1| |Shift| |Ans| |1| |=|

Or set the calculator to gradian.
Press the buttons in sequence;
|Shift| |Mode| |3|

Then,
|4| |5| |0| |Shift| |Ans| |3| |=|

450 gradians to radian
450^g/1^r = 9π/4 radians

Press the buttons in sequence;
|4| |5| |0| |Shift| |Ans| |3| |⁌/⁌| |1| |Shift| |Ans| |1| |=|

Or set the calculator to radian
Press the buttons in sequence;
|Shift| |Mode| |4|

Then,
|4| |5| |0| |Shift| |Ans| |3| |=|

This technique could really save your time.
Now, you just have to practice this technique until this becomes a default formula to you.
Hope you learned something today!

Btw guys, I used the emulator for calculator in this post. To download the emulator, here is the link of my previous post that will guide you in downloading and installing the application.

Thank you for your time!

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Yours truly,

@strings