EXERCISE 9 4 ARC LENGTH AND SECTOR AREA - PUNJAB-CURRICULUM-AND-TEXTBOOK-BOARD-PCTB / 10TH-CLASS / MATHEMATICS / MATHEMATICS-10-10TH-CLASS-NBF-2024 / CHORD-AND-ARCS-OF-A-CIRCLE / EXERCISE-9-4-ARC-LENGTH-AND-SECTOR-AREA

Example

A circular decoration piece consists of two equal parts as shown in the figure. Find the length of one part of the piece. What is the cost of decoration piece @ Rs.8 per centimetre?

Solution

Given that r = 56 cm theta = 90 deg then:

l = \frac{θ}{360^{\circ}} \times 2 π r = \frac{90^{\circ}}{360^{\circ}} \times 2 \times \frac{22}{7} \times 56

l = 88 c m

Length of one part of the decoration piece is = 2 x 88 = 176 cm

Cost of decoration piece @ Rs.8 per cm = Rs. 2 x 176 x 8 = Rs.2,816

Exercise 9.4

Exercise 9.4: Arc Length and Sector Area

Example

Solution