## Can related acute angles be negative?

These can be positive or negative and are defined in terms of the principal angle. The related acute angle is the positive angle between the terminal arm and the x-axis. It is always less than 90°.

## Is acute angle always positive?

Reference Angle: the acute angle between the terminal arm/terminal side and the x-axis. In other words, the reference angle is an angle being sandwiched by the terminal side and the x-axis. It must be less than 90 degree, and always positive.

Why is related acute angle always positive?

Because if you think about quadrants of a circle, an acute angle is in the upper right quadrant of the circle. The ratios (sim/cos/tan) therefore are all positive since the distances involved are all positive – that is they are to the right or upwards from the origin.

Is an acute angle positive or negative?

Positive acute angles are those measured counterclockwise from initial to final position of the ray and whose size is less than 90o (i.e π2 radians), that is less than the right angle.

### Are related angles negative?

In particular, reference angles are never negative. A reference angle can be zero: this happens when the original angle’s terminal point lies on the x -axis. That is, the reference angle is zero whenever the original angle’s terminal point is either (1,0) or (−1,0) .

### How do you determine if an acute angle is related?

If the terminal arm is in quadrant 2, do 180∘ minus the principle angle to find the related acute angle. If the terminal arm is in quadrant 3, do the principle angle minus 180∘ to find the related acute angle. If the terminal arm is in quadrant 4, do 360∘ minus the principle angle to find the related acute angle.

How do you find a positive acute angle?

To do this, consider a right triangle drawn on the coordinate axes. The positive acute angle θ will be the angle created between the x -axis and the hypotenuse of the triangle. The lengths of the two legs of the triangle will be the x and y coordinates of a point in the first quadrant.

How do you solve an acute angle?

Divide the length of side “a” by the length of the hypotenuse, side “c.” This is the sine of the acute angle that shares the horizontal leg with the right angle. Enter this ratio into your scientific calculator and use the inverse sine function to determine the angle.

#### What is the related acute angle for?

The related acute angle is the angle formed by the terminal arm of an angle in standard position and the x-axis. The related acute angle lies between 0º and 90º. Example 1: The point P(–5, –4) lies on the terminal arm an angle in standard position.

#### What angle is acute?

Acute angles measure less than 90 degrees. Right angles measure 90 degrees. Obtuse angles measure more than 90 degrees.

How do you determine if an acute angle is positive?

Can reference angles be zero?

A reference angle can be zero: this happens when the original angle’s terminal point lies on the x -axis. That is, the reference angle is zero whenever the original angle’s terminal point is either (1,0) or (−1,0) .