Law of Cosines | Find all the missing measures | SSS

The video tutorial explains how to solve a triangle problem using the law of cosines and the law of sines. It begins by setting up the problem with given side lengths and discusses why the law of cosines is necessary. The tutorial then demonstrates how to calculate the largest angle, angle C, using the cosine formula. After finding the largest angle, the law of sines is used to find the remaining angles, with a focus on avoiding rounding errors. The video concludes with tips on using these trigonometric laws effectively.

Why can't the Law of Sines be used initially in this problem?

• Because the sides are not in proportion.

• Because the sides are not equal.

• Because there are no angles given.

• Because the triangle is not right-angled.

What is the first step when using the Law of Cosines with three sides given?

• Use the Law of Sines first.

• Calculate the perimeter of the triangle.

• Find the smallest angle first.

• Find the largest angle first.

What is the formula used to find angle C using the Law of Cosines?

• cos(C) = (a^2 + b^2 - c^2) / (2ab)

• cos(C) = (b^2 + c^2 - a^2) / (2bc)

• cos(C) = (c^2 + a^2 - b^2) / (2ca)

• cos(C) = (b^2 + a^2 - c^2) / (2ba)

What is the result of using the cosine inverse function on a calculator?

• It gives the perimeter of the triangle.

• It gives the side length.

• It gives the angle in degrees.

• It gives the area of the triangle.

Why is it important to avoid using rounded answers when using the Law of Sines?

• It simplifies the process.

• It makes the calculation faster.

• It is not necessary to avoid rounded answers.

• It can lead to incorrect results.

What should you do if you're unsure about the ambiguous case when using the Law of Sines?

• Use a different formula.

• Ignore the ambiguous case.

• Use the Law of Cosines instead.

• Guess the angle.

What is the correct way to find the remaining angles after finding the largest angle?

• Use the Law of Sines for one angle and subtract from 180.

• Use the Law of Cosines for all angles.

• Use the Law of Sines for all angles.

• Guess the remaining angles.

What is the main advantage of using the Law of Cosines over the Law of Sines?

• It is more accurate.

• It is faster.

• It is easier to understand.

• It requires fewer calculations.

What should you do if you make a mistake while typing variables in the Law of Cosines?

• Recheck and correct the variables.

• Ignore the mistake.

• Start the problem over.

• Use the Law of Sines instead.

What is the final step in solving for all angles in a triangle using the Law of Cosines and Sines?

• Subtract the known angles from 180.

• Divide the angles by 3.

• Multiply the angles by 2.

• Add all angles together.