Answer:
Surface area of the wood to be painted = ( + r
)
- 16
Step-by-step explanation:
Surface area of a cone is given as the sum of the surface area and the area of its base.
i.e Surface area = +
Lr
where: L is the length of its slant height and r is the radius.
Applying the Pythagoras theorem,
L =
Thus,
Surface area = r (r +
)
The given cylindrical hole has a radius of 4 cm and depth 2 cm.
The area of one of its circular surfaces =
= ×
= 16
The surface area of the piece of wood to be painted = surface area of cone - area of cylindrical circular surface.
Surface area of the wood to be painted = r (r +
) - 16