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: This’s the answer for your question 12.405
Answer:
Step-by-step explanation:
5x + 1 is a SUM.
3y is a TERM.
9(5x + 1) is a PRODUCT.
9 is a FACTOR of 9(5x + 1).
5x + 1
---------- is a QUOTIENT.
3y
5 is the COEFFICIENT of x.
X² + 2x +3
If the discriminent Δ = b²-4.a.c <0 , that means the roots (or the zero value) are nit REAL Number (they are imaginary or complex)
Δ = 2² - 4(1)3) = 4 - 12 = -8
since Δ = - 8 < 0 there are no real roots