True I hope this helps I'm no 100% sure tho I haven't done this type of math in a while
know what is the third side length
the difference between the 2 other sides < the greatest side of triangle < the sum of 2 other sides
so here the answers here could be ( 10- 17 - 20)
10-8 < 13 < 10+8
13-8 < 17 < 13+8
13-8 < 20 < 13+8
297 I think because 45+21=66, then x9= 594 divided by 2 is 297
Option A:

Solution:
<u>To evaluate tan(105)°:</u>
105° can be written as sum of 60° and 45°.
tan(105)° = tan(45 + 60)°
Using the summation identity:


We know that, tan(45)° = 1 and tan(60)° = √3
Substitute this in the above equation.


To rationalize the denominator multiply by the conjugate
.

Using exponent formula:
and 

Using exponent formula: 





Hence option A is the correct answer.