# How to find an angle using law of sines

## How do you find angles with the same sine?

To find angles with same Trig Function value, here’s what you can do:

1. For sine, if sin x = A, then the angle (180-x) will give you sin (180 -x) = sin x=A.
2. For cosine, if cos y = B, then the angle (360-x) will give you cos (360-y)= cos y = B.

## How do you find an angle with two sides not right angle?

Derivation of the law of cosines

The law of cosines can be used to find the measure of an angle or a side of a non-right triangle if we know: two sides and the angle between them or. three sides and no angles.

## How do you find an angle with two sides and one angle?

“SAS” is when we know two sides and the angle between them. use The Law of Cosines to calculate the unknown side, then use The Law of Sines to find the smaller of the other two angles, and then use the three angles add to 180° to find the last angle.

## What angle is cos1?

The answer is 120°. With inverse cosine, we select the angle on the top half of the unit circle. Thus cos-1 (–½) = 120° or cos-1 (–½) = 2π/3. In other words, the range of cos-1 is restricted to [0, 180°] or [0, π].

## What angles are sine and cosine the same?

In a right triangle, the sine of one acute angle, A, equals the cosine of the other acute angle, B. Since the measures of these acute angles of a right triangle add to 90º, we know these acute angles are complementary.

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## How do you find Coterminal angles?

To find a positive and a negative angle coterminal with a given angle, you can add and subtract 360° if the angle is measured in degrees or 2π if the angle is measured in radians . Example 1: Find a positive and a negative angle coterminal with a 55° angle.

## How do you find an angle using trigonometry?

Find the angle of elevation of the plane from point A on the ground.

1. Step 1 The two sides we know are Opposite (300) and Adjacent (400).
2. Step 2 SOHCAHTOA tells us we must use Tangent.
3. Step 3 Calculate Opposite/Adjacent = 300/400 = 0.75.
4. Step 4 Find the angle from your calculator using tan-1

## How do you find the size of an angle?

Divide that known length by the sine of its opposite angle. If the length measures six inches divide six by 0.574 to get 10.45. Find the sine of the angle opposite to the unknown length. If this angle is, for instance, 80 degrees: sin (40) = 0.643.

## How do I find the measure of an angle?

Using a Protractor

The best way to measure an angle is to use a protractor. To do this, you’ll start by lining up one ray along the 0-degree line on the protractor. Then, line up the vertex with the midpoint of the protractor. Follow the second ray to determine the angle’s measurement to the nearest degree.

## Is SOH CAH TOA only for right triangles?

Q: Is sohcahtoa only for right triangles? A: Yes, it only applies to right triangles. … A: They hypotenuse of a right triangle is always opposite the 90 degree angle, and is the longest side.