Answer:
-a+11
Step-by-step explanation:
hard to explain. but should be correct
Answer:
13-gon
Step-by-step explanation:
The sum of the interior angles of a polygon with n sides is:
S = 180° (n − 2)
If S = 1980°, then:
1980° = 180° (n − 2)
11 = n − 2
n = 13
Answer:
yes
Step-by-step explanation:
Explanation:
First, we need to find the values of the sine and cosine of x knowing the value of tan x and x being in the 3rd quadrant. Since tan x = 5/12, using Pythagorean theorem, we know that

Note that both sine and cosine are negative because x is in the 3rd quadrant.
Recall the addition identities listed below:









Therefore, the expression reduces to


