Assertion: If we rotate a right angled triangle of height 5 cm and base 3 cm about its base, we get cone of height 3 cm and base 5 cm
Reason : Plane figures are of 2 dimensions and solid shapes are of 3 dimensions.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false
D. If assertion is false but reason is true.

Answer

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that if we rotate a right-angled triangle with a height of 5 cm and a base of 3 cm about its base, we will get a cone with a height of 3 cm and a base of 5 cm.

### Step 2: Analyzing the Rotation
When we rotate the triangle around its base:
- The base of the triangle (3 cm) will become the radius of the cone.
- The height of the triangle (5 cm) will become the height of the cone.

### Step 3: Conclusion from Rotation
Thus, after rotation:
- The radius of the cone is 3 cm (from the base of the triangle).
- The height of the cone is 5 cm (from the height of the triangle).

Therefore, the assertion is **false** because it incorrectly states that the height of the cone is 3 cm instead of 5 cm.

### Step 4: Understanding the Reason
The reason states that plane figures are of 2 dimensions and solid shapes are of 3 dimensions. This statement is true.

### Step 5: Final Evaluation
- The assertion is **false**.
- The reason is **true**.

### Conclusion
The correct answer is that the assertion is false, but the reason is true.

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