How to Put Degree Mode on A Graphing Calculator

When working with trigonometric functions on a graphing calculator, it's essential to ensure your calculator is set to degree mode. This guide explains how to switch your graphing calculator to degree mode and why it matters for accurate calculations.

Why Use Degree Mode?

Most graphing calculators default to radian mode, which is useful for advanced mathematics and calculus. However, degree mode is more intuitive for everyday applications and basic trigonometry.

In degree mode:

The full circle is 360 degrees
Common angles like 30°, 45°, 60°, and 90° are easy to work with
Trigonometric functions (sin, cos, tan) return values that match standard tables

Note: Some scientific calculators use "DEG" for degree mode while graphing calculators may use "Deg" or "Degree". Check your specific model's manual.

How to Switch to Degree Mode

The process varies slightly by calculator model, but here are the general steps:

For TI-84 Plus Series:

Press the MODE button
Use the arrow keys to highlight Degree
Press ENTER to select degree mode

For Casio fx-CG50:

Press the SHIFT button
Press the F1 button (Mode)
Use the arrow keys to select Degree
Press EXE to confirm

For HP Prime:

Press the MODE button
Select Angle from the menu
Choose Degree from the options

Verification: After switching, calculate sin(30) to confirm you get approximately 0.5. If you get a different value, your calculator may still be in radian mode.

Common Mistakes

Many students make these errors when working with degree mode:

Assuming all calculators use the same menu structure
Forgetting to verify the mode after switching
Confusing degree mode with gradian mode (which uses 400 grads per circle)
Not checking the mode before entering trigonometric functions

Always double-check your calculator's mode before performing calculations, especially when working with angles.

Practical Example

Let's say you need to find the height of a tree using a 30° angle of elevation:

Set your calculator to degree mode
Measure the distance from the tree to be 50 feet
Calculate: height = distance × tan(30°)
On your calculator: 50 × tan(30°) ≈ 28.87 feet

Remember: If your calculator is in radian mode, tan(30°) would be approximately -0.1425, giving an incorrect negative height.

FAQ

What happens if I forget to switch to degree mode?

Your trigonometric calculations will be incorrect. For example, sin(30°) should be 0.5, but in radian mode it would be approximately -0.9880.

Can I use degree mode for all calculations?

Yes, degree mode is perfectly fine for basic trigonometry, geometry, and everyday applications. It's only necessary to switch to radian mode for advanced calculus or physics problems.

How do I know if my calculator is in degree mode?

Check the display for a "Deg" or "Degree" indicator. Alternatively, calculate sin(30°) - it should be approximately 0.5 in degree mode.

What if my calculator doesn't have a degree mode?

Some basic calculators only support radian mode. In this case, you'll need to convert degrees to radians by multiplying by π/180 before performing trigonometric functions.