Fill in the blank

(i) Four

AB, BC, CD and DA are four sides of this quadrilateral

A quadrilateral is polygon having four sides and four corners.

(ii) four

A, B, C and D are four angles of this quadrilateral

A quadrilateral is polygon having four sides and four corners.

(iii) Four, collinear

A, B, C and D are the four vertices of this quadrilateral.

In quadrilateral, no three out of four vertices are collinear. If all the vertices are collinear then we will get a line segment and if three out of four vertices is collinear, we will get a triangle.

(iv) two

A diagonal is a line segment that joins two opposite vertices of the quadrilateral.

AC and BD are the two diagonals of the quadrilateral ABCD.

(v) opposite

A diagonal is a line segment that joins two opposite vertices of the quadrilateral.

AC and BD are the two diagonals of the quadrilateral ABCD.

(vi) 360^o

ABCD is a quadrilateral and AC is a diagonal. Now, we get two triangles

∆ ABC and ∆ ACD.

As we know that sum of angles of triangle is 180°

So, sum of two triangles will be 180° X 2 = 360°

i.e., the sum of the angles of a quadrilateral is 360°