If a = half then what is 4 (a-1)= ?

Step-by-step explanation:

a=1/2

4(a-1)

put value of a

4(1/2-1)

4(1/2)

2

you would use (d.) the law of cosines or a^2 = b^2 + c^2 – 2bc(cos a)

, b^2 = a^2 + c^2 – 2ac(cos b), or c^2 = a^2 + b^2 - 2ab(cos c). you wouldn't use b. the law of sines as it is mostly effective when 1side and 2angles are given. a and c aren't the answer for they are the improper versions of the law of cosines. hope this is .

your answer is  

d.

196.5 m2

step-by-step explanation: