Answer:
Do you still need this one?
Step-by-step explanation:

It’s going to be the area of the triangle on the side times the length, so 0.5 x 36 x 15 x 48 = 12960
Answer:
140°
Step-by-step explanation:
<3 = 40 because they are vertical angles
<3 +<4 = 180 because they are same side interior angles
40 + <4 = 180
Subtract 40 from each side
40-40 + <4 = 180-40
<4 = 140
Recall the Maclaurin expansion for cos(x), valid for all real x :

Then replacing x with √5 x (I'm assuming you mean √5 times x, and not √(5x)) gives

The first 3 terms of the series are

and the general n-th term is as shown in the series.
In case you did mean cos(√(5x)), we would instead end up with

which amounts to replacing the x with √x in the expansion of cos(√5 x) :
