Answer:
[tex]b = 537[/tex]
Step-by-step explanation:
For this triangle we have to
[tex]a=640\\A=70\°\\B=52\°[/tex]
Now we use the sine theorem to find the length of b:
[tex]\frac{sin(A)}{a}=\frac{sin(B)}{b}=\frac{sin(C)}{c}[/tex]
Then:
[tex]\frac{sin(A)}{a}=\frac{sin(B)}{b}\\\\b=\frac{sin(B)}{\frac{sin(A)}{a}}\\\\b=a*\frac{sin(B)}{sin(A)}\\\\b=(640)\frac{sin(52)}{sin(70)}\\\\b=537[/tex]
