Commonly we might need to measure the angle of an inclined, θ.

Method 1: Protractor

This is typically achieved with a protractor. However, care must be taken as the centre of the protractor circle is usually not along the base of the plastic protractor.

Typical protractor where the centre of the
protractor is not along the base.

Example of a protractor in which the centre is along the base.

Note that although the centre point of the protractor does not lie along the base of the protractor it can still be used to measure the angle of inclination of this ramp.

 

Method 2: Calculation

A more precise method would be to measure x and h and then calculate θ from the tangent function.

e.g.     x = 97.6 cm, h = 12.6 cm

tan θ = opposite / adjacent = 12.6/97.6 = 0.129

Therefore θ = 7.4°

(This is a higher precision than can be measured using a protractor.)

 

Practical Skills