Suppose you revolve the plane region completely about the given line to sweep out a solid of revolution. Describe the solid. The
n find its surface area in terms of pi.
1 answer:
Answer:
The answer is explained below
Step-by-step explanation:
The question is not complete, the complete question is Suppose you revolve the plane region completely about the given line to sweep out a solid of revolution. Describe the solid. Then find its surface area in terms of pi.
i) about the y axis
ii) about the x axis
Also the image is attached below.
Answer:
i) about the y axis
If it is revolved about the y axis, the solid produced is a cone with a radius of of 4 units (r = 4) and a height of 3 units (h = 3). The surface area of the cone is:
Surface area = πr (r + √(r² + h²)) = π × 4 (4 + √(4² + 3²)) = 4π (4 + √25) = 4π (4 + 5) = 4π × 9 = 36π unit²
ii) about the x axis
From the image attached, If it is revolved about the x axis, the solid produced is a cone with a radius of of 3 units (r = 3) and a height of 4 units (h = 4). The surface area of the cone is:
Surface area = πr (r + √(r² + h²)) = π × 3 (3 + √(4² + 3²)) = 3π (3 + √25) = 3π (3 + 5) = 3π × 8 = 24π unit²
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Answer:
The no. of possible handshakes takes place are 45.
Step-by-step explanation:
Given : There are 10 people in the party .
To Find: Assuming all 10 people at the party each shake hands with every other person (but not themselves, obviously) exactly once, how many handshakes take place?
Solution:
We are given that there are 10 people in the party
No. of people involved in one handshake = 2
To find the no. of possible handshakes between 10 people we will use combination over here
Formula :
n = 10
r= 2
Substitute the values in the formula
No. of possible handshakes are 45
Hence The no. of possible handshakes takes place are 45.
We have been given that a company makes wax candles in the shape of a solid sphere. Each candle has a diameter of 15 cm. We are asked to find the number of candles that company can make from 70,650 cubic cm of wax.
To solve our given problem, we will divide total volume of wax by volume of one candle.
Volume of each candle will be equal to volume of sphere.
, where r represents radius of sphere.
We know that radius is half the diameter, so radius of each candle will be cm.
Now we will divide 70,650 cubic cm of wax by volume of one candle.
Therefore, 40 candles can be made from 70,650 cubic cm of wax.