Loonie has three wooden sticks measuring 17 inches, 21 inches, and 25 inches. He lays them down to form a triangle. Find the measure of the angle enclosed by 17 inches and 21 inches. (Express answers to the nearest hundredths) (using the law of cosines)

Correct answer:

γ =  81.5435 °

Step-by-step explanation:

a=17 in b=21 in c=25 in  c2 = a2+b2  2 a b cos γ  2 a b cos γ = a2+b2c2  k = cos γ  k=2 a ba2+b2c2=2 17 21172+212252=3450.1471  γ=π180°arccosk=π180°arccos0.1471=81.5435=81°3237"

Try calculation via our triangle calculator.

Did you find an error or inaccuracy? Feel free to write us. Thank you!

Tips for related online calculators
Need help calculating sum, simplifying, or multiplying fractions? Try our fraction calculator.
The Pythagorean theorem is the base for the right triangle calculator.
Do you want to convert time units like minutes to seconds?
Cosine rule uses trigonometric SAS triangle calculator.
See also our trigonometric triangle calculator.
Try conversion angle units angle degrees, minutes, seconds, radians, grads.

You need to know the following knowledge to solve this word math problem:

We encourage you to watch this tutorial video on this math problem: video1   video2   video3

Related math problems and questions: