Question

The curved surface area and the height of a right circular cylinder are 660 cm2 and 10 cm respectively. Find its diameter (in cm)

Answer 1

Answer:

21cm

Step-by-step explanation:

• first you substitute your formula ;curved surface area= pi × diameter × height

• then you rewrite with the numerals you have been given                                660cm2=3.1415 × d × 10cm
• you divide 3.1415 in both sides,so it will be;                                                   3.1415÷660cm2=3.1415÷3.1415 × d × 10cm
• so it will be;                                                                                                           210cm = 10cm × d                                                                                              
• then divide 10cm in both sides ;                                                                               10 ÷ 210cm =10cm ÷10 × d

Answer 2

Curved surface area of the cylinder = 2πrh =

$\sf{660 {cm}^{2}}$

$\longrightarrow$ $\sf{2\times \frac{22}{7} \times r \times 15 = 660}$

$\longrightarrow$ $\sf{r = \frac{660 \times 7}{2 \times 22 \times 15} cm = 7cm}$

$\therefore$ Diameter of the cylinder = 14cm