Question

Perimeter and area of a pencil

Answer 1

Answer:

Perimeter of a pencil:

Perimeter = πr + 2h + 2l

• πr :

(Perimeter semicircular part of pencil, i.e. it's end part)

• 2h :

(Perimeter of the rectangular structure)

• 2l :

(Perimeter of lead)

____________________

Area of pencil:

Area = πr²/2 + 2rh + πr (r + l)

• πr²/2 :

(Area of semicircular end)

• 2rh :

(Area of rectangular part)

• πr (r + l) :

(Area of lead)

Area = r [ πr/2 + 2h + π (r + l) ]

Note:

Here l = √(r² + H²), H = height of the lead.