The area to be painted orange
= CSA of cone + Base area of Cone – Base area of the cylinder
Curved Surface Area of Cone
Given that diameter of conical portion = 5cm
The radius of conical portion = 5/2 = 2.5 cm
Height of the conical part = h = 6cm
We need to find the ‘l’ first
We know that
l2 = h2 + r2
⇒ l2 = 62 + (2.5)2
⇒ l2 = 36 + (6.25)
⇒ l2 = 42.25
⇒ l = √42.25
⇒ l = 6.5cm
So, CSA of conical portion = πrl
=3.14×2.5×6.5
= 51.025 cm2
Base area of the cone = πr2
=3.14×2.5×2.5
=19.625 cm2
Diameter of the cylinder = 3cm
So, Radius of the cylinder = 1.5cm
Base area of the cylinder = π(r’)2
=3.14×1.5×1.5
=7.065 cm2
So, the area to be painted orange = 51.025 + 19.625 – 7.065
= 63.585 cm2
Now, the area to be painted yellow
= CSA of the cylinder + Area of one bottom base of the cylinder
= 2πr’h’ + π(r’)2
= 2 × 3.14 × 1.5 × 20 + 7.065
= 188.4 + 7.065
= 195.465 cm2