To find the answer, use this equation:
65 + 45 + x = 180
Simplify:
110 + x = 180
Subtract:
x = 70
Your unknown interior is 70
Hope this helps!! :)
B(Bread) D(Drink) M(Meat)
B1+D1+M1
B1+D1+M2
B1+D1+M3
B1+D2+M1
B1+D2+M2
B1+D2+M3
B1+D3+M1
B1+D3+M2
B1+D3+M3
B2+D1+M1
B2+D1+M2
B2+D1+M3
B2+D2+M1
B2+D2+M2
B2+D2+M3
B2+D3+M1
B2+D3+M2
B2+D3+M3
Making there be 18 different combinations.
We have a formula for that( according to the Intersecting chords theorem)

3×4=2×jk
6=jk