Question

Show that b=7 Please help i have 10 minutes to answer

Answer 1

Answer:

The value of Cos(60°) is ½

Step-by-step explanation:

B)as we know

b²=a²+c²-2ac.cos(b)

b=√5²+8²-2.5.8×cos(60°)

b=√25+64-80×½

b=√25+64-40

b=√89-40

b=√49

b=7 (proven)