## How do you find a side of a triangle given two sides?

Right Triangles and the Pythagorean Theorem

1. The Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2 , can be used to find the length of any side of a right triangle.
2. The side opposite the right angle is called the hypotenuse (side c in the figure).

## How do you find the third side of an obtuse triangle?

To still be obtuse, it has to have the 3rd side such that it creates greater than a right triangle. So calculate the 3rd side for a right triangle, and make it slightly larger. 16 squared plus 21 squared = 3rd side squared.

How do you find the third side and perimeter of a triangle given two sides?

Method 1 of 3: Finding the Perimeter When Three Side Lengths are Known. Remember the formula for finding the perimeter of a triangle. For a triangle with sides a, b and c, the perimeter P is defined as: P = a + b + c.

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

### How do you find the length of the third side of an acute triangle?

Correct answer: The sum of the lengths of 2 sides of a triangle must be greater than—but not equal to—the length of the third side. Further, the third side must be longer than the difference between the greater and the lesser of the other two sides; therefore, 20 is the only possible answer.

### What is the length of a triangle?

The Law of Sines says that for all angles of a triangle, the ratio of the sine of that angle to its opposite side will always be the same. The length of side c is 2.98. The Law of Cosines says you can determine the length of any triangle side if you know its opposite angle and the lengths of the other two sides.

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

To use the Law of Sines to find a third side:

1. Identify angle C. It is the angle whose measure you know.
2. Identify a and b as the sides that are not across from angle C.
3. Substitute the values into the Law of Cosines.
4. Solve the equation for the missing side.

How do you calculate the third angle of a triangle?

All you’ve got to do is subtract the other angle measurements from 180° to get the measurement of the third angle. The sum of the interior angles of a triangle is equal to 180°. To find the third angle of a triangle when the other two angles are known subtract the number of degrees in the other two angles from 180 0.

#### What is the measure of the third side of a triangle?

The perimeter of the triangle is 22 cm. and the third side measure is half of the sum of that of the first and the second sides. The second side is 8 cm + 4 cm = 12 cm long in accordance with the problem condition. The third side is (8 cm + 12 cm)/2 = 10 cm long in accordance with the problem condition.

#### How to find third side of a triangle?

Identify angle C. It is the angle whose measure you know.

• Identify a and b as the sides that are not across from angle C.
• Substitute the values into the Law of Cosines.
• Solve the equation for the missing side.
• What is the formula for determining sides of a triangle?

How to find the sides of a right triangle if leg a is the missing side, then transform the equation to the form when a is on one side, and take a square root: a = √ (c² – if leg b is unknown, then b = √ (c² – a²) for hypotenuse c missing, the formula is c = √ (a² + b²)