The diagram presents an unfinished scale drawing used to determine the resultant of two $10\,\text{N}$ forces acting at a point in the directions indicated. What is the size of the resultant force?
- A$7.5\,\text{N}$
- B$8.6\,\text{N}$
- C$18\,\text{N}$
- D$20\,\text{N}$