Addition Formula Question

Hi there,

I have a problem involving a right angled triangle ABC. It is right angled at C.

The hypoteneuse has a value of 13 units.

A line stretches across the triangle from B to side AC at D. Side AC is divided into AD and DC. DC has the value 4 units.

Angle ABD equals x degrees and angle DBC equals 30 degrees.

I have to find the exact value of sin x.

I have worked out that side BC has a value of 6.928 units. Hypoteneuse BD has a value of 7.9 units and side AD equals 7 units.

Can anyone give me help with this problem please?

Thank you,

Cromlix