Advertisements
Advertisements
प्रश्न
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
उत्तर
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
संबंधित प्रश्न
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.
The circumferences of two circles are in the ratio 2: 3. What is the ratio between their areas?
Find the area of a quadrant of a circle whose circumference is 88 cm.
The side of a square is 10 cm. Find the area of the circumscribed circle. [π = 3.14]
In the given figure, ABCD is a trapezium of area 24.5 cm2 , If AD || BC, ∠DAB = 90°, AD = 10 cm, BC = 4 cm and ABE is quadrant of a circle, then find the area of the shaded region.
The diameter of a circle is 5.6 cm. Find its circumference.
Find the area and perimeter of the following semicircles: Diameter = 7cm
Find the circumference of a circle whose area is 81πcm2.
The sum of the circumference and diameter of a circle is 176 cm. Find the area of the circle.
A cart wheel makes 9 revolutions per second. If the diameter of the wheel is 42cm, find its speed in km per hour. (Answer correct to the nearest km)
