How to use the law of cosines to find the missing parts of a triangle

The video tutorial explains how to determine the largest side or angle using the Law of Cosines. It provides a detailed calculation of angle B, followed by the use of the Law of Sines to find angle C, considering both acute and obtuse possibilities. Finally, it demonstrates how to calculate angle A using the angle sum property, ensuring the sum of angles equals 180 degrees.

What is the formula used to calculate side B in a triangle using the Law of Cosines?

• b^2 = a^2 + c^2 - 2ac * cos(B)

• b^2 = a^2 + c^2 + 2ac * cos(B)

• b^2 = a^2 - c^2 - 2ac * cos(B)

• b^2 = a^2 - c^2 + 2ac * cos(B)

After correcting arithmetic errors, what is the calculated value of angle B?

• 86.18 degrees

• 90.00 degrees

• 45.00 degrees

• 60.00 degrees

Which law is used to find angle C after determining angle B?

• Law of Cosines

• Law of Sines

• Pythagorean Theorem

• Law of Tangents

What is the acute angle C calculated using the Law of Sines?

• 45.00 degrees

• 90.00 degrees

• 116.10 degrees

• 63.89 degrees

How do you determine the remaining angle A in a triangle?

• Adding angles B and C

• Subtracting the sum of angles B and C from 180 degrees

• Using the Law of Cosines

• Using the Law of Sines

What is the calculated value of angle A?

• 45.00 degrees

• 90.00 degrees

• 29.92 degrees

• 60.00 degrees

Why is it important to verify the sum of angles in a triangle?

• To ensure the angles add up to 360 degrees

• To ensure the angles add up to 180 degrees

• To confirm the triangle is equilateral

• To check if the triangle is isosceles