# How do you find the side length of a triangle given the angles?

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## How do you find the side length of a triangle given the angles?

Given angle and hypotenuse Apply the law of sines or trigonometry to find the right triangle side lengths: a = c * sin(α) or a = c * cos(β) b = c * sin(β) or b = c * cos(α)

**How do you find the length of a side of a triangle with two angles?**

Answer: If you know two angles, then you can work out the third since all the angles sum to 180 degrees. If the sides are a, b and the hypotenuse is c (opposite angle A), and the angles are A, B and C, then Sin A = a/c, so a = cSin A. Also Cos A = b/c, so b = cCos A.

### How do you find a side with 3 angles?

We must use The Law of Cosines first to find any one of the three angles, then we can use The Law of Sines (or use The Law of Cosines again) to find a second angle, and finally Angles of a Triangle to find the third angle. See Solving “SSS” Triangles .

**How do you find the length of one side of a triangle given two sides?**

Add the two known angles together and subtract the total from 180. All angles inside a triangle must add up to 180 degrees. Calculate the sine of the new angle by entering it in the calculator and hitting the “sin” button. Multiply the answer by X and this gives you the length of the unknown side.

## What is the formula to find the opposite side of a triangle?

If you know the hypotenuse, h, and the adjacent side x, then the opposite side y = √(h2-x2). If you know the angle, θ, and the hypotenuse, then y = h sin(θ).

**How do you find third side of a triangle?**

Finding the Length of the Hypotenuse You can use the Pythagorean Theorem to find the length of the hypotenuse of a right triangle if you know the length of the triangle’s other two sides, called the legs. Put another way, if you know the lengths of a and b, you can find c.

### What is the rule for side lengths of a triangle?

According to the Triangle Inequality Theorem, the sums of the lengths of any two sides of a triangle must be greater than the length of the third side.