Question

CosA=7/8 where a=2,b=3 find c

Answer 1

Answer:

c=4, 5/4 but we generally didn't use fraction so c =4

Step-by-step explanation:

cosA =b²+c²-a²/2bc formula

7/8=9+c²-4/2x3c

7/8=5+c²/6c

42c=8(5+c²)

42c=40+8c²

0=8c²-42c+40

0=2(4c²-21c+20)

0=4c²-16c-5c+20

0=4c(c-4) -5(c-4)

0=(4c-5)(c-4)

c=5/4, c=4