Jawaban:

583 cm^2

Penjelasan:

Let the ;ength, breadth, height of cuboidal block be 15 cm,10 cm, and 5 cm respectively.

Total surface area of solid cuboidal block

= 2(lb+bh+lh)

=2(15x10+10x5+15x5) cm^2

=2(150+50+75 )= 2(275) = 550 cm^2

Radius of cylindrical hole = r 7/2 cm

Area of two circular bases

= r^2 + r ^2 = 2 r^2

= 2 x 22/7 x 7/2 x 7/2 = 77 cm^2

Curved surface area ofcylinder = 2 rh

= 2 x 22/7 x 7/2 x 5 = 110 cm^2

Required area = (area of cuboidalblock - area of two circular bases + area of cylinder )

= (550+110-77) cm^2 = 583 cm^2