1) ,
,
,
(given)
2) (reflexive property)
3) (SSS)
4) (CPCTC)
5) and
are right angles (perpendicular lines form right angles)
6) and
are right triangles (a triangle with a right angle is a right triangle)
7) (HA)
8) (CPCTC)
Firstly, we can look at our givens,
a = 17
b = 22
c = 30
And we are looking for m∠A
Is the Law of Cosines. Now we can solve for our unknown, m∠A. This will give us
Now we can substitute in our given variables.
Then we can plug this into our calculator which will give us
34.19185257 degrees
Now we just have to round to the nearest tenth
This means that the answer is 34.2 degrees