FINDING ANGLES IN OTHER QUADRANTS USING REFERENCE ANGLES

The reference angle is the acute angle formed between the terminal arm and the x-axis. The reference angle is always positive and measures between 0° and 90°.

To determine the other angles in other quadrants using reference angles and the following table.

The reference angle always be lesser than 90 degree.

Question :

Copy and complete the table. Determine the measure of each angle in standard position given its reference angle and the quadrant in which the terminal arm lies.

Solution :

(a)  72

Let θ be given angle.

Required angle in 4^th quadrant  =  360 - θ 

  =  360 - 72  =  288

Hence the required angle is 288.

(b)  56

Let θ be given angle.

Required angle in 2^nd quadrant  =  180 - θ 

  =  180 - 56  =  124

Hence the required angle is 124.

(c)  18

Let θ be given angle.

Required angle in 3^rd quadrant  =  180 + θ 

  =  180 + 18  =  198

Hence the required angle is 198.

(d)  35

Let θ be given angle.

Required angle in 4^th quadrant  =  360 - θ 

  =  360 - 35  =  325

Hence the required angle is 325.

Apart from the stuff given in this section, if you need any other stuff in math, please use our google custom search here.

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.