Need help with this mathswatch question-did half don't know where i am going wrong

a) is correct

b) CD = 15,1 cm

Step-by-step explanation:

The cosine law can be used here:

b² = d² + c² - 2dc*cosβ

b² = 18² + 12,1² - 2 * 18 * 12,1 * cos 56°

b = √226,82

b = 15,1 cm

Least common multiplue is the smallest number that the 2 numbers can multiply into  so exg LCM of 3 and 2 is 6,
to find, find the factors
12=2 times 2 times 3
18=2 timeds 3 times 3
so combine all of them
in 12, we have 2  2's and 1 three
in 18, we have 1 2 and 2 3's so
we must have 2 2's and 2 3's so
2 times 2 times 3 times 3=36=lcm\
so find factors and group

lcm=36