Observe the following figures to find the opposite vertex angle (excluding horizontal angle) (1) As shown in figure a, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (2) As shown in Figure B, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (3) As shown in Figure C, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (4) This paper studies the relationship between the number of straight lines and the logarithm of opposite vertex angle in (1) ～ (3). If n straight lines intersect at a point, how many pairs of opposite vertex angle can be formed? (5) If there are 2008 lines intersecting at a point, how many pairs of vertex angles can be formed?

Observe the following figures to find the opposite vertex angle (excluding horizontal angle) (1) As shown in figure a, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (2) As shown in Figure B, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (3) As shown in Figure C, there are & nbsp; & nbsp; pairs of vertex angles in the figure; (4) This paper studies the relationship between the number of straight lines and the logarithm of opposite vertex angle in (1) ～ (3). If n straight lines intersect at a point, how many pairs of opposite vertex angle can be formed? (5) If there are 2008 lines intersecting at a point, how many pairs of vertex angles can be formed?

(1) As shown in figure a, there are two pairs of vertex angles in the figure;
(2) As shown in Figure B, there are 6 pairs of vertex angles in the figure;
(3) As shown in Figure C, there are 12 pairs of vertex angles;
(4) This paper studies the relationship between the number of straight lines and the logarithm of opposite vertex angle in (1) ～ (3). If n straight lines intersect at a point, how many pairs of opposite vertex angle can be formed?
There are n straight lines intersecting at a point to form 2n angles. The calculation formula is: [(1 + 2n) * n-3n] / 2 = n (n-1) opposite vertex angle
(5) If there are 2008 lines intersecting at a point, how many pairs of vertex angles can be formed?
According to the above formula = 2008 * 2007 = 4030056 pairs of vertex angle