. A toy is in the form of a cone of radius 3.5 cm mounted on a hemisphere of same radius.
The total height of the toy is 15.5 cm. Find the total surface area of the toy.es I
Answers
Right circular cone
Solve for surface area
A≈213.21cm²
r Radius
3.5
cm
h Height
15.5
cm
Using the formulas
A=πrl+πr2
l=r2+h2
Solving forA
A=πr(r+h2+r2)=π·3.5·(3.5+15.52+3.52)≈213.20692cm²
Answer:
214.5 cm² is the correct answer.
Step-by-step explanation:
Given,
- Common Radius of the toy = 3.5 cm
- Total Height of the toy = 15.5 cm
- ∴ Height of the cone = 15.5 - 3.5 = 12 cm
Total Surface Area of the toy = Curved Surface Area of Cone + Curved Surface Area of Hemisphere
= (π × r × l) + (2 × π × r²)
= π × r × (l + 2r)
In the Cone, we have Base and Height. So we can calculate the Slant Height of the cone by using Pythagorean Formula.
⇒ (l)² = (b)² + (h)²
⇒ l = √(12.25 + 144)
= √156.25
= 12.5 cm
⇒ π × r × (l + 2r)
⇒ 22/7 × 3.5 × (12.5 + 7)
⇒ 22 × 0.5 × 19.5
⇒ 214.5 cm² ←ANSWER