Question

UURGENTTT PLLZ HELP WILL MARK AS BRANLIEST!!!

Answer 1

Answer:

Surface area of the wood to be painted =  ($r^{2}$ + r $\sqrt{h^{2} + r^{2} }$ )$\pi$ - 16$\pi$

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 = $\pi$$r^{2}$ + $\pi$Lr

where: L is the length of its slant height and r is the radius.

Applying the Pythagoras theorem,

                        L = $\sqrt{h^{2} + r^{2} }$

Thus,

                Surface area  =  $\pi$r (r + $\sqrt{h^{2} + r^{2} }$ )

The given cylindrical hole has a radius of 4 cm and depth 2 cm.

The area of one of its circular surfaces = $\pi$$r^{2}$

                                                   = $\pi$ × $(4)^{2}$

                                                   = 16$\pi$ $cm^{2}$

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 = $\pi$r (r + $\sqrt{h^{2} + r^{2} }$ ) - 16$\pi$