Q8 of 52 Page 145

In figure 7.11, a toy made from a hemisphere, a cylinder and a cone is shown. Find the total area of the toy.

Radius of circular region, r = 3cm


Height of Cylinder, H = 40cm


Height of cone, h = 4cm


As we know,


Surface area of hemisphere, AH = 2πr2


Surface area of cylinder, Acy = 2πrH


Surface area of cone is,




ACO = 5πr


Total area = AH + ACY + ACO


On substituting the values, we get,


⇒ Total area = πr(2r + 2H + 5)


⇒ Total area = π× 3× (6 + 80 + 5)


⇒ Total area = 273π


∴ total area of the figure is 273π sq. cm


More from this chapter

All 52 →
6

Observe the measures of pots in figure 7.8 and 7.9. How many jugs of water can the cylindrical pot hold?

 7

A cylinder and a cone have equal bases. The height of the cylinder is 3 cm and the area of its base is 100 cm2.The cone is placed upon the cylinder. Volume of the solid figure so formed is 500 cm3. Find the total height of the figure.

 9

In the figure 7.12, a cylindrical wrapper of flat tablets is shown. The radius of a tablet is 7 mm and its thickness is 5 mm. How many such tablets are wrapped in the wrapper?

 10

Figure 7.13 shows a toy. Its lower part is a hemisphere and the upper part is a cone. Find the volume and the surface area of the toy from the measures shown in the figure.(π= 3.14)