Hi,
The answer will be
.
Now how is that, there is a rule for the right angled triangle which says:
cosθ =
so, if we applied this rule on the lower triangle we can say: cos30°= 
and therefore the hypotenuse = 
= 
.
now in the upper triangle we will apply the same rule so,
cos45°=
and the adjacent side in the upper triangle is and the hypotenuse is x.
so cos45°=
and then we can say
x=
= .
The answer will be
Now how is that, there is a rule for the right angled triangle which says:
cosθ =
now in the upper triangle we will apply the same rule so,
cos45°=
and the adjacent side in the upper triangle is
so cos45°=
x=