1. Given any triangle ABC with sides BC=a, AC=b and AB=c, the following are true :
i) the larger the angle, the larger the side in front of it, and the other way around as well. (Sine Law) Let a=20 in, then the largest angle is angle A.
ii) Given the measures of the sides of a triangle. Then the cosines of any of the angles can be found by the following formula:

2.

3. m(A) = Arccos(-0.641)≈130°,
4. Remark: We calculate Arccos with a scientific calculator or computer software unless it is one of the well known values, ex Arccos(0.5)=60°, Arccos(-0.5)=120° etc
Answer:
#3: x is approximately 0.37, -5.37, #4: x is approximately 4.19, -1.19
Step-by-step explanation:
You can solve using the quadratic equation or by solving with the perfect square
= 
x is approximately 0.37, -5.37
Answer:
there is no picture... but i will try my best to help you if you post picture in another question
Answer:
no
Step-by-step explanation:
clue what this means LOLOLOL
To find out how many hours it rained, divide the total rise in the river by the amount it rose every hour.

First convert the mixed number into an improper fraction. We do this by multiplying the denominator to the whole number, adding it to the numerator, which becomes our new numerator, and we keep the denominator the same:

When dividing fractions we flip(the reciprocal) the one we're dividing by and multiply:

Multiply the numerators and denominators together:

Simplify by dividing:

So it rained for 10 hours.