Datos :
<img src="https://tex.z-dn.net/?f=a%3D3%5C%2Cm%5C%5Cb%3Dx%5C%5Cc%3Dx%5C%5CA%3D30%5E%7Bo%7D%5C%5CC%3D90%5E%7Bo%7D%5C%5CB%3D180%5E%7Bo%7D-90%5E%7Bo%7D-30%5E%7Bo%7D%3D60%5E%7Bo%7D" />
Luego aplicando la ley de los senos para encontrar la altura asd tiene :
<img src="https://tex.z-dn.net/?f=%5Cfrac%7Ba%7D%7BSenA%7D%3D%5Cfrac%7Bb%7D%7BSenB%7D%5C%2C%5Ctextsf%7B%28despejando%20a%20nos%20queda%3A%29%7D%5C%5C%20aSenB%3DbSenA%5C%5C%20a%3D%5Cfrac%7BbSenA%7D%7BSenB%7D%5C%2C%5Ctextsf%7Bsustituyendo%7D%20%5C%5C%20a%3D%5Cfrac%7B3Sen30%5E%7Bo%7D%7D%7BSen60%5E%7Bo%7D%7D%5C%5C%20a%3D1.73%5C%2Cm" />
Para encontrar c o la longitud aplicamos el Teorema de Pitagoras :
<img src="https://tex.z-dn.net/?f=c%5E%7B2%7D%3Da%5E%7B2%7D%2Bb%5E%7B2%7D%5C%5C%20c%3D%5Csqrt%7Ba%5E%7B2%7D%2Bb%5E%7B2%7D%7D%5C%5C%20c%3D%5Csqrt%7B%281.73%29%5E%7B2%7D%2B3%5E%7B2%7D%7D%5C%5C%20c%3D3.4%5C%2Cm" />
Saludos.