I wish I could explain how to do these, but I can recommend Math-way. You can type the equations in and it with simplify it for you. It will even show you the steps, but you have to pay fro that part, but at least it will give you the answer.
Answer:
33.3 in²
Step-by-step explanation:
Apply the formula for finding the area of triangle that has an included angle and two given sides, which is, Area = ½*a*b*Sin*C
Where,
a = 7 in
b = 13 in
C = 133°
Plug in the values
Area = ½*7*13*Sin(133)
Area = 33.2765935 ≈ 33.3 in² (nearest tenth)
No, not always.
Yes in some cases, like 100 is greater than 0. But -100 is less than zero. So it depends on the number.