Question

Draw a decagon with diagonals ​

Answer 1

Answer:

In a decagon, you can draw a diagonal from any of the 10 vertices to 7 other vertices. (The two adjacent vertices and the vertex itself cannot be used to get a diagonal.) Each diagonal has two vertices, so as not to count each diagonal twice, you take half of the product of 10 x 7. The answer is 35 diagnosis.