Alright, lets get started.
Please refer the diagram, I have attached.
As per formula SOH CAH TOA,
![Tan B = (opposite)/(adjacent)](https://img.qammunity.org/2019/formulas/mathematics/high-school/5ni7v84868dnkqin1unfsc2llt5v3gdwqd.png)
As per given values, angle B = 61
side b = 33.2
Putting the value back in formula
![Tan 61 = (33.2)/(a)](https://img.qammunity.org/2019/formulas/mathematics/high-school/ke1alq3qc2059cpryt71yx0jpxtjq5kqkq.png)
Putting the value of tan 61
![1.80 = (33.2)/(a)](https://img.qammunity.org/2019/formulas/mathematics/high-school/ucokupvlmfewmh8c39r1wmgy6pmmapmkpw.png)
Multiplying a on both sides
![a*1.80 = (33.2)/(a) * a](https://img.qammunity.org/2019/formulas/mathematics/high-school/h7bv2o1nj3jyftvyd79h3ka43ndo3mip64.png)
a * 1.80 = 33.2
Dividing 1.80 in both sides
![(a*1.80)/(1.80) = (33.2)/(1.80)](https://img.qammunity.org/2019/formulas/mathematics/high-school/kyqj1kr38jtdn9opcl25njpz0hkyypu18l.png)
a = 18.4 : Answer
Hope it will help :)