(13.1^2-b^2 15.2^2 30^2)/(2*1​3.1*15.2)=​1.461

calculate b value

[Alex Mcaulley]

What is the question?

[Vladimir Sovkov]

What does it have to do with Matlab? Quite obvious the solution is

Answer 1

[Shota Kato]

syms b 
fun = (13.1^2 - b^2 * 15.2^2 * 30^2 ) / (2*13.1*15.2)==1.461;
ans = solve(fun)

ans =

-(25638665^(1/2)*1i)/114000

(25638665^(1/2)*1i)/114000

25638665^(1/2) / 114000

ans =

0.0444