Question

*If the total surface area of ​​a cylinder is 440 square cm and the radius is 7 cm, what is its height?*

1️⃣ 7 cm
2️⃣ 3 cm
3️⃣ 10 cm
4️⃣ 440/7 cm​

Answer 1

Answer:

$\star\;\underline{\boxed{\sf{\pink{h = 3.009cm \approx \: 3cm}}}}$

Step-by-step explanation:

Question:

If the total surface area of a cylinder is 440 square cm and the radius is 7 cm, what is its height?

1) 7 cm

2) 3cm

3) 10cm

4) $\sf\cfrac{440}{7} \: cm$

Given:

$\star\;\underline{\boxed{\sf{\pink{Total\ surface\ Area\ of\ the\ cylinder =\ \bf 440^2\ cm}}}}$

$\star\;\underline{\boxed{\sf{\pink{Radius\ of\ the\ cylinder =\ \bf 7\ cm}}}}$

To find:

• $\sf{\blue{Height\ of\ the\ cylinder}}$

Solution:

$\star\ \: \underline{\boxed{\sf{\orange{Total\ surface\ Area\ of\ the\ cylinder =\ \bf 2πr(h+r)\ cm^2}}}}$

$\bf{ \orange{ 2 \times 3.14 \times 7(h + 7) = 440}}$

$\bf{ \orange{6.28 \times 7h + 49 = 440}}$

$\bf{ \orange{7h + 49 = \cfrac{440}{6.28}}}$

$\bf {\orange{7h + 49 \: = 70.063}}$

$\bf \orange{7h \: = 21.063}$

$\star\;\underline{\boxed{\sf{\pink{h = 3.009cm \approx \: 3cm}}}}$