Question
There is a 12 m tall hoarding pole on the top of a
building. A person at some distance from the building, observes that the angle of elevation to the top of the hoarding pole from that point is the same as the angle of elevation to the bottom of the hoarding pole if he moves 4 √ 3 m closer to the building. What is the angle of elevation that the person is seeing?Solution
Let AB be the building of height ‘h’ and BC be the hoarding pole of height 12 m. Let θ be the angle of elevation as seen by the person at a distance of ‘x’ m and ‘x + 4 √ 3‘ m. In Δ DAB, tan θ = h/x (i) In Δ EAC, tan θ = (h + 12)/ (x + 4 √ 3) (ii) From (i) and (ii) h/x = (h + 12)/ (x + 4 √ 3) ⇒ hx + 4 √ 3h = hx +12x ⇒ h/x = 12/ 4 √ 3 = √ 3 ⇒ tan θ = h/x = √ 3 = tan 60° ⇒ θ = 60°
If the circumference of a circle is 44 cm then find the area of the circle?
The angle of elevation of the top of a tower from a point on the ground which is 45 meters. away from the foot of the tower is 30Β°. The height of the t...
Mr. Arun rows a boat with the stream at 10 km/hr and against the stream in 5 km/hr. In still water, his rate of rowing in km/h is:
In the figure given below, PQRS is a parallelogram in which PN and PM are perpendicular to QR and RS, respectively. If RS = 81 cm, PM = 42 cm and PN = 5...
What is the volume of a cylinder if the radius of the cylinder is 12cm, and the height is 15 cm? (Take Ο = 3.14)
PQRS is a rectangle. T is a point on PQ such that RTQ is an isosceles triangle and PT = 5 QT. If the area of triangle RTQ is 12 β3 sq.cm, then the ar...
If the volume and radius of a cylinder is 24640 cm3 and 28 cm respectively then find the height of the cylinder?
If the volume and radius of a cylinder is 7700 cm3 and 14 cm respectively then find the height of the cylinder?
The length of sides of a square is twice the radius of a circle and perimeter of a rectangle is half the perimeter of the square. If the sum of length a...
If the numerical value of twice the curved surface area of a right circular cylinder is equal to the numerical value of its volume, then what is the num...