True or False

1. The process of finding six unknown elements of a triangle is called the solution of triangle?
2. Application of trigonometry is usually applied in the fields of Navigation and Astronomy?
3. Right angled triangle is also an oblique triangle?
4. The circle passing through the vertices of a triangle is called circumcircle?
5. Sum of opposite angles of cyclic quadrilateral is 360^{0}.
6. Triangle is the only rigid rectilinear figure?