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Case Study: The length of the perimeter of a slice of a pizza in the form of a sector of circle is…

Mathematics20254 marksCase based
Case Study: The length of the perimeter of a slice of a pizza in the form of a sector of circle is 20 cm. $r$ be the radius of the circle, sectorial angle be $\theta$ radian and $l$ be the length of the arc. Based on the above information, answer the following questions.
Figure for this question
(a)[1.0]
Express the radius of the sector in terms of sectorial angle $\theta$ radian.
(b)[1.0]
Let A be the area of the slice. Then, express A in terms of r.
(c)[1.0]
For the maximum value of A, find the value of the sectorial angle.
(d)[1.0]
Maximum area of the slice of the pizza is ____.

Answer

Answer (a)

Official answer key
$r = \frac{20}{\theta + 2}$

Final answer: $\frac{20}{\theta+2}$

Answer (b)

Official answer key
$10r - r^2$

Answer (c)

Official answer key
$2^c$

Final answer: 2 radian

Answer (d)

Official answer key

Blanks: $25\ \text{cm}^2$

$25\ \text{cm}^2$
Applications of Derivatives

From ISC 2025 Practice Mathematics, question 98.