Here you can use proportion:
The ratio betwen €1.2 to £1
is the same as the ratio between €180 to £x
Mathematically this means that
\(\dfrac{1.2}{180} =\dfrac{1}{x}\).
Now
\(1.2\cdot x=180\cdot 1\\\\ x=\dfrac{180}{1.2} \\ \\x=150\)
Answer: €180 is £150
