Area Problems The ratio of the area of square of side a and equilateral triangle of side a is? 4 :3 4 : ?3 2 :1 2 : ?3 4 :3 4 : ?3 2 :1 2 : ?3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of area = a2/ ?(3/4) a2= 4/?3 = 4:?3
Area Problems In a circle of radius 21 cm an arc subtends an angle of 72° at the centre. The length of the arc is? 19.8 cm 21.6 cm 13.2 cm 26.4 cm 19.8 cm 21.6 cm 13.2 cm 26.4 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Arc length = 2?r (?° / 360°) = 2 x (22/7) x 21 x (72° / 360°) cm= 26.4 cm
Area Problems The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is? 31.68 km/hr. 36.25 km/hr. 32.72 km/hr. 29.46 km/hr. 31.68 km/hr. 36.25 km/hr. 32.72 km/hr. 29.46 km/hr. ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Circumference = 2?r = 2 x (22 / 7) x 70 cm = 440 cm Distance travelled in 10 revolutions = 440 x 10 cm = 4400 cm = 44 m? Speed = distance / time= 44 / 5 m/sec= (44 / 5) x (18 / 5) km/hr = 31.68 km/hr
Area Problems A rectangle has 15 cm as its length and 150 cm 2 as its area .Its area is increased to 1 1 / 3 times the original area by increasing only its length . Its new perimeter is? 50 cm 70 cm 60 cm 80 cm 50 cm 70 cm 60 cm 80 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Breadth of the rectangle = (150/15) cm= 10 cmNew area = (4/3 x 150) cm2= 200 cm2New length = 200/10 cm=20 cmNew perimeters = 2(20 + 10) cm= 60 cm
Area Problems A circle and a square have same area. The ratio of the side of the square and the radius of the circle is? ?? : 1 1 : ?? 1 : ? ? : 1 ?? : 1 1 : ?? 1 : ? ? : 1 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? Area of square = Area of circle ? x2 = ?r2? x/r = ?? = ? ? : 1
Area Problems The length of a rectangle is double while its breadth is halved. What is the percentage change in area? 75 50 No change None of these 75 50 No change None of these ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let length = l and breadth = bThen, area = lb New length = 2lAnd new breadth = b/2 ? New area = ( 2l ) x (b/2) = lbSo, there is no change in area .
EXAMIANS