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
A wire is looped in the form of a circle of radius 28 cm. It is re-bent into a square form. Determine the length of the side of the square.
A sector is cut from a circle of radius 21 cm. The angle of the sector is 150º. Find the length of its arc and area.
If the circumference of a circular sheet is 154 m, find its radius. Also find the area of
the sheet. (Take `pi = 22/7`)
The adjacent sides of a parallelogram ABCD measure 34 cm and 20 cm, and the diagonal AC measures 42 cm. Find the area of the parallelogram.
In the given figure, ABCD is a square of side 4 cm. A quadrant of a circle of radius 1 cm is drawn at each vertex of the square and a circle of diameter 2 cm is also drawn. Find the area of the shaded region. [Use π = 3.14.]
A square ABCD is inscribed in a circle of radius r. Find the area of the square.
A race track is in the form of a rig whose inner circumference is 352 m and outer circumference is 396 m. Find the width and the area of the track.
Find the diameter of the sphere for the following :
Surface Area = 221. 76 cm2
A bucket is raised from a well by means of a rope which is wound round a wheel of diameter 77 cm. Given that the ascends in 1 minute 28 seconds with a uniform speed of 1.1 m/sec, calculate the number of complete revolutions the wheel makes in raising the bucket. (Take π =22/7)
Sudhanshu divides a circular disc of radius 7 cm in two equal parts. What is the perimeter of each semicircular shape disc? (Use π = `22/7`)
