Can anyone help me with this

[vernal tulip]

It's a trigonometric question

[hardy aurora]

You can use the cosine rule here

[buoyant crane]

At one glance, I think that we might need the cosine addition(or difference) formula

[vernal tulip]

Ok

[modest bridge]

Cosine rule a^2=b^2+c^2+2bc cos(A)

[crystal lagoon]

Point D is making the confusion, you can ignore that to use cosine rule based on ABC triangle.

[modest bridge]

The point d splits the triangle in 2 right angles that's it

And you can then use in think basic trig

[native pawn]

You might use basic trigonometric formula to find AD , then find BD and deduce the angle DBC then find DC and sum AD + DC .
Hint : cos a = adjacent side / hypothenus ; sin a = opposite side / hypothenus

[uncut hawk]

Hey, dont know if u still need help with this but i think u could approach with this approach:

1. calculate AD and BD using AB * sinA or cos A
2. with AD and BC, u can find sinC
3. with sin C, u can find cosC
4. with cosC, u can find DC
   with AD and DC, u have AD + DC = AC
   do not round up the number every step