How to use law of cosines for SSS

The video tutorial explains how to find the angles of a triangle given its sides using trigonometric laws. It starts by identifying the need to find angles in a side-side-side triangle and choosing the angle opposite the longest side to calculate first. The law of cosines is applied to find angle B, which is obtuse. Then, the law of sines is used to find angle A, and finally, angle C is calculated by subtracting the sum of angles A and B from 180 degrees.

What is the first step in solving a triangle when only the side lengths are known?

• Calculate the perimeter of the triangle

• Use the Law of Cosines

• Use the Law of Sines

• Find the area of the triangle

Why is it beneficial to find the angle opposite the longest side first?

• It is always an acute angle

• It helps determine the nature of the other angles

• It is the smallest angle in the triangle

• It simplifies the calculation of the triangle's area

What does it mean if one angle in a triangle is obtuse?

• The triangle is isosceles

• The other two angles must be acute

• The other two angles must also be obtuse

• The triangle is equilateral

What is the significance of knowing that angle B is obtuse in this problem?

• It confirms that the triangle is right-angled

• It means the triangle is scalene

• It ensures that angle A must be obtuse

• It confirms that the other two angles are acute

Which trigonometric law is used to find the remaining angles after determining one angle using the Law of Cosines?

• Law of Tangents

• Law of Sines

• Pythagorean Theorem

• Law of Secants

What is the final step in solving for all angles in a triangle?

• Multiply the angles by the side lengths

• Subtract the known angles from 180 degrees

• Divide the angles by the number of sides

• Add all angles to check if they sum to 360 degrees

How do you calculate angle C after finding angles A and B?

• By using the Law of Tangents

• By adding angles A and B

• By subtracting angles A and B from 180 degrees

• By using the Law of Cosines again