Chapter 4.1, Problem 34E

(a)

To determine

Find the angle ${87.9}^0$ lies in which quadrant.

Answer to Problem 34E

First Quadrant

Explanation of Solution

Given: The angle ${87.9}^0$

Concept Used:

Quadrants are usually denoted by roman letters I, II, III and IV as shown in the figure below:

• Angles between 0° and 90° are in the first quadrant.
• Angles between 90° and 180° are in the second quadrant.
• Angles between 180° and 270° are in the third quadrant.
• Angles between 270° and 360° are in the fourth quadrant.

Calculation:

  $0^0<{87.9}^0<{90}^0$; The angle ${87.9}^0$ lies in the First quadrant.

Thus, the angle ${87.9}^0$ lies in the First quadrant.

(b)

To determine

Find the angle $-{8.5}^0$ lies in which quadrant.

Answer to Problem 34E

Fourth Quadrant

Explanation of Solution

Given: The angle $-{8.5}^0$

Concept Used:

Quadrants are usually denoted by roman letters I, II, III and IV as shown in the figure below:

• Angles between 0° and 90° are in the first quadrant.
• Angles between 90° and 180° are in the second quadrant.
• Angles between 180° and 270° are in the third quadrant.
• Angles between 270° and 360° are in the fourth quadrant.

Calculation:

Calculation:

A Negative angle measured in clockwise direction from the Horizontal axis .

Thus, theangle $-{8.5}^0$ lies in Fourth Quadrant.