How many diagonals can be drawn by joining the vertices of an octagon?
20
Concept used :
Number of diagonals in polygon = [n(n - 3)]/2 (where n is the number of sides)
Calculations :
Here n will be 8 as octagon has 8 sides.
Number of polygons in octagon = [8 × (8 - 3)]/2
⇒ (8 × 5)/2
⇒ 40/2 = 20
∴ Option 1 will be the right choice.
Important Questions from Quadrilaterals
What is the value of AC 2– BD 2
What is the area of the parallelogram?
The area of a rectangle is 300 cm 2and the length of its diagonal is 25 cm. The perimeter of the rectangle (in cm) is:
The adjacent angles of a rhombus are in the ratio of 3 : 6. The smallest angle of the rhombus is:
The area of a trapezium is 18 sq.cm. Its height and base are 3 cm and 5 cm respectively. Find the length of the side parallel to the base.
