Question

Why is 270° a quadrantal angle?

It is on the y-axis
It is an obtuse angle
It is a multiple of 90˚
It is equivalent to 90˚

Answer 1

A Quadrantal Angle is an angle in standard position with terminal side on the x-axis or y-axis. Some examples are the angles located at 0°, 90°, 180°, 270°, 360°, 450°, ... as well as -90°, -180°, -270°, -360°

Answer 2

Option 1 and 3 - It is on the y-axis and It is a multiple of 90˚.

Explanation:

To find : Why is 270° a quadrantal angle?

Solution :

Quadrantal Angle is defined as

One that is in the standard position and has a measure that is a multiple of 90° (or
`(\pi)/(2)` radians).

A quadrantal angle will have terminal side on the x-axis or y-axis.

i.e. the angles 0°, 90°, 180°, 270°, 360°, 450°, ... as well as –90°, –180°, –270°, –360°, ...

By definition,

270° is a Quadrantal angle as it is on y-axis and it is a multiple of 90°.

Therefore, option 1 and 3 is correct.