How to use the law of cosines to find out no triangles exist

The video tutorial covers constructing and labeling triangles, understanding triangle proportions, and selecting the appropriate cosine formula. It demonstrates applying the law of cosines to solve for unknowns in a triangle. The tutorial concludes with error checking, revealing that the given dimensions do not form a valid triangle.

What is the first step when working with laws of sines and cosines?

• Memorize all formulas.

• Estimate the side lengths.

• Draw and label a triangle.

• Calculate the angles directly.

Why might the law of cosines be preferred over the law of sines?

• It is always more accurate.

• It requires fewer calculations.

• It is easier to remember.

• It is used when there is no ratio of a side length to its angle.

Which angle should be used in the law of cosines formula?

• The smallest angle.

• Any angle can be used.

• The angle opposite the shortest side.

• The angle opposite the longest side.

What is the result when the calculated angle is 180 degrees?

• The triangle is isosceles.

• The triangle is equilateral.

• No triangle is possible.

• A valid triangle is formed.

What should you do if the side lengths do not form a valid triangle?

• Adjust the side lengths to fit.

• Conclude that no triangle is possible.

• Assume the triangle is right-angled.

• Recalculate using different formulas.