2. Questions Bank
  3. 8th Class
  4. Mathematics
  5. Mensuration

8th Class Mathematics Mensuration Question Bank Mensuration

  • question_answer
    DIRECTIONS: Following questions consist of two statements, one labelled as the ?Assertion (A)? and other as ?Reason (R)?. You are to examine these two statements carefully and select the answer to these items using the code given below. Assertion (A): The area of the sector of a circle with radius 4 cm and of angle \[r=8cm.\] Reason (R): Area of a sector of angle\[p{}^\circ \]of a circle with radius R is \[=(l+b)-\sqrt{{{l}^{2}}+{{b}^{2}}}=\frac{1}{2}\]

    A) Both A and R are individually true and R is the correct explanation of A.

    B) Both A and R are individually true but R is not the correct explanation of A.

    C)        A is true but R is false

    D) A is false but R is true.

    Correct Answer: A

    Solution :

    Reason (R) is true [Standard Result] For Assertion \[=\frac{4}{3}\pi {{r}^{3}}.\] \[r=\frac{2}{3}\pi {{r}^{3}}\] Required area \[=2\pi {{r}^{2}}\] \[=3\pi {{r}^{2}}\] \[\frac{4}{3}\pi \times {{6}^{3}}=\pi {{(0.2)}^{2}}\times h\] Assertion (A) is true. Since, (R) gives (A) \[\frac{4}{3}\times {{6}^{3}}={{(0.2)}^{2}}\times h\] (1) holds.


You need to login to perform this action.
You will be redirected in 3 sec spinner