Question

शंकु की त्रिज्या और ऊँचाई 4:3 के अनुपात में है। यदि शंकु के आधार का क्षेत्रफल 154 वां सभी है तो छ
कुल पृष्ठीय क्षेत्रफल ज्ञात कीजिए।​

Answer 1

Answer:

22

Step-by-step explanation:

Let suppose the answer is X

4:3 = 154

4x + 3x = 154

7x = 154

x = 154÷7

x = 22

Answer 2

Total surface area would be 346.5 unit²

Step-by-step explanation:

We know that,

The base area of a cone,

$B=\pi r^2$

Where, r is the radius of the cone,

We have,

B = 154 unit²,

⇒ $\pi r^2 = 154$

$\frac{22}{7} r^2 = 154$

$r^2 =\frac{154\times 7}{22}$

$r^2 = 7\times 7$

$r^2 = 7^2$

$\implies r = 7$

Now, radius and height are in the ratio of 4 : 3,

If h represents height,

$\frac{7}{h}=\frac{4}{3}$

$\implies h =\frac{21}{4}$

Also, the total surface area of a cone,

A = base area + curved surface area

$A=154 + \pi r \sqrt{r^2 + h^2}$

$=154 +\frac{22}{7}\times 7 \sqrt{7^2 +(\frac{21}{4})^2}$

$=154 + 22\sqrt{49 +\frac{441}{16}}$

$=154 + 22\sqrt{\frac{784+441}{16}}$

$=154 + 22\sqrt{\frac{1225}{16}}$

$=154 + 22\times \frac{35}{4}$

$=154 + 192.5$

= 346.5 unit²

#Learn more:

Find the curved surface area and total surface area of the each of the following right circular cones

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