Area Problems The length of each side of an equilateral triangle having an area of 4?3 cm 2 is? ?3/4 cm 3 cm 4/?3 cm 4 cm ?3/4 cm 3 cm 4/?3 cm 4 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of equilateral triangle = ?3/4 a2 = 4?3.? a2 = 16? a = 4 cm
Area Problems The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 72.6 cms 42 ? 3 cms 168 cms 126 cms 72.6 cms 42 ? 3 cms 168 cms 126 cms ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 22/7 x r2 = 462? r2 = (462 x 7) /22 = 147? r = 7?3 cm ? Height of the triangle = 3r = 21?3 cmNow, ? a2 = a2/4 + (3r)2? 3a2/4 = (21?3)2? a2 = (1323 x 4)/3? a = 21x 2 = 42 cm? Perimeter = 3a = 3 x 42=126 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. 29.46 km/hr. 36.25 km/hr. 32.72 km/hr. 31.68 km/hr. 29.46 km/hr. 36.25 km/hr. 32.72 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 tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 75 paise per sq m is Rs. 558 Rs. 358 Rs. 458 Rs. 258 Rs. 558 Rs. 358 Rs. 458 Rs. 258 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area to be plastered = 2 l + b × h + l × b = 2 25 + 12 × 6 + 25 × 12 = 744 s q . m Cost of plastering = 744 × 75 100 = R s . 558
Area Problems The ratio of the area of the circumcircle and the incircle of a square is 1 : 2 1 : ?2 2 : 1 ?2 : 1 1 : 2 1 : ?2 2 : 1 ?2 : 1 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of the areas of the circumcircle and incircle of a square = [(Diagonal)2?] / [(Side)2?]= [(Side x ?2)2] / (Side)2 = 2/1 or 2 : 1
Area Problems The ratio of the corresponding sides of two similar triangles is 3 : 4, The ratio of their areas is? ? 3: 2 9 : 16 3 : 4 4 : 3 ? 3: 2 9 : 16 3 : 4 4 : 3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of similar triangle = Ratio of the square of corresponding sides = (3x)2 / (4x)2 = 9x2 / 16x2 = 9/16 = 9 : 16
EXAMIANS