Math Labs with Activity – To make a Right-Circular Cone
To make a right-circular cone of given slant height and radius of base.
- A sheet of chart paper
- A pair of scissors
- A geometry box
- A pencil
- A roll of Sellotape
Step 1: Let the given slant height of the cone be l and the radius of the base be r.
Step 2: Calculate the circumference of the base of the required cone as 2πr.
Step 3: From the chart paper cut out a circular piece having centre at a point O and radius l as shown in Figure 35.1.
Step 4: Also, mark a sector AOB on this circle such that the arc AB =2πr as shown in Figure 35.1.
Step 5: Cut the sector AOB and roll it so as to join the two radii OA and OB. Join these two ends with Sellotape to get the desired cone as shown in Figure 35.2.
The above experiment provides a method of making a right-circular cone out of a circular sheet of paper.