Advertisements
Advertisements
Question
A photograph of Billiard/Snooker table has dimensions as `1/10`th of its actual size as shown in the following figure:
The portion excluding six holes each of diameter 0.5 cm needs to be polished at rate of ₹ 200 per m2. Find the cost of polishing.
Advertisements
Solution
Actual length = 25 × 10 = 250 cm
Actual breadth = 10 × 10 = 100 cm
Area of table = 250 × 100 = 25000 cm2
Radius of 1 hole = `0.5/2` = 0.25 cm
Area of 6 holes = 6 × πr2 = `6 xx 22/7 xx 0.25 xx 0.25` = 1.18 cm2
Area of portion excluding holes = 25000 – 1.18 = 24998.8 cm2
∴ Cost of polishing = ₹ `24999/10000 xx 200` = ₹ 500 (approx.)
APPEARS IN
RELATED QUESTIONS
In Figure, find the area of the shaded region [Use π = 3.14]
Choose the correct alternative answer for the following question.
The curved surface area of a cylinder is 440 cm 2 and its radius is 5 cm. Find its height.
Find the diameter of the circle whose area is equal to the sum of the areas of two circles having radii 4 cm and 3 cm.
The radius of a circular garden is 100 m. There is a road 10 m wide, running all around it. Find the area of the road and the cost of levelling it at Rs 20 per m2. [Use π = 3.14]
A hollow metallic cylindrical tube has an internal radius of 3.5 cm and height 21 cm. The thickness of the metal tube is 0.5 cm. The tube is melted and cast into a right circular cone of height 7 cm. Find the radius of the cone, correct to one decimal place.
Using a ruler and compasses only:
(i) Construct a triangle ABC with the following data: AB = 3.5 cm, BC = 6 cm and ∠ ABC = 120°.
(ii) In the same diagram, draw a circle with BC as diameter. Find a point P on the circumference of the circle which is equidistant from AB and BC.
(iii) Measure ∠ BCP.
Diameters of different circles are given below. Find their circumference (Take π = `22/7`)
d = 56 m
In reference to a circle the value of π is equal to ______.
The circumference of a circle whose area is 81 πr2, is ______.
