Lesson Example Discussion Quiz: Class Homework |
Step-5 |
Title: Circles |
Grade: 1400-a Lesson: S3-L1 |
Explanation: Hello Students, time to practice and review the steps for the problem. |
Lesson Steps
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
A circular pond is of diameter 17.5 m. It is surrounded by a 2 m wide path. Find the cost of constructing the path at the rate of Rs. 25 per square meter (Use π = 3.14). |
|
2 |
Step |
Given |
d = 17.5 m and wide = 2 m and rate = 25 |
3 |
Hint |
\$ r = d/2\$ \$r = 17.5/2\$ r = 8.75 |
|
4 |
Tip |
Calculate the outer radius of the path |
Outer Radius = Radius of Pond + Width of Path |
5 |
Step |
Substituting the given values |
Outer radius = 8.75 + 2 = 10.75 |
6 |
Hint |
Calculate the area of the outer circle |
|
7 |
Formula: |
The area of a circle is given by the formula |
\$A = π times r^2\$ |
8 |
Step |
Substituting the given values |
\$"Area of Outer Circle" = π times ("Outer Radius")^2\$ \$= 3.14 times (10.75 m)^2\$ = 362.85 |
9 |
Tip |
Calculate the area of the inner circle (pond) |
|
10 |
Step |
Substituting the given values |
\$"Area of Inner Circle" (Pond) = π times ("Radius of Pond")^2\$ \$= 3.14 times (8.75 m)^2\$ = 240.39 |
11 |
Step |
Calculate the area of the path and Substituting the values |
Area of Path = Area of Outer Circle - Area of Inner Circle Area of path = 362.85 - 240.39 Area of path = 122.46 |
12 |
Step |
Calculate the cost of constructing the pathway and substitute the values |
\$"Cost" = "Area of Path" times "Cost per square meter"\$ \$"Cost" = 122.46 times 25\$ Cost = Rs.3061.5 |
13 |
Step |
Therefore, the cost of constructing the path at the rate of Rs. 25 per square meter is Rs. 3061.5 |
|
14 |
SumUp |
Can you summarize what you’ve understood in the above steps? |
|
15 |
Choice.A |
Incorrect. This option may be the closest, but it could result from rounding or calculation errors |
Rs. 3061 |
16 |
Choice.B |
The result is wrong due to rounding errors or calculation mistakes |
Rs. 3062.5 |
17 |
Choice.C |
The answer is correct because it matches the calculated value |
Rs. 3061.5 |
18 |
Choice.D |
The result is wrong due to rounding errors or calculation mistakes |
Rs. 3062 |
19 |
Answer |
Option |
C |
20 |
SumUp |
Can you summarize what you’ve understood in the above steps? |
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