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CBSE Class 10 Answered

A spherical balloon of radius r subtends an angle Φ at the eye of an observer.  If the angle of elevation of its centre is Φ , then find the height of the centre of the balloon .
Asked by pdcavita | 19 Nov, 2017, 02:53: PM
answered-by-expert Expert Answer
 
begin mathsize 16px style Let space straight O space be space the space centre space of space the space balloon space of space radius space straight r space and space straight P space be space the space eye space of space an space observer. Let space PA comma space PB space be space the space tangents space from space straight P space to space the space balloon. Then comma space angle APB equals straight alpha rightwards double arrow angle APO equals angle BPO equals straight alpha over 2 Let space OL space be space perpendicular space from space straight O space on space the space horizontal space PX. AT space the space centre comma space angle OPL equals straight beta In space triangle OAP comma sin space straight alpha over 2 equals OA over OP equals straight r over OP rightwards double arrow OP equals straight r space cosec space straight alpha over 2 In space triangle OPL comma sin space straight beta equals OL over OP rightwards double arrow OL equals OP space sin space straight beta equals straight r space cosec space straight alpha over 2 space sin space straight beta end style
Answered by Rashmi Khot | 30 Nov, 2017, 10:42: AM

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CBSE 10 - Maths
Two pillars are standing on either side of a 80 m wide road. Height of one pillar is 20 m more than the height of the other pillar. From a point on the road between the pillars, the angle of elevation of the higher pillar is 60°, whereas that of the other pillar is 30°. Find the position of the point between the pillars and the height of each pillar. (Use √3 = 1-73)
Asked by swetalinasamantaray022 | 21 Mar, 2023, 04:15: PM
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CBSE 10 - Maths
On a warm and lazy Saturday, Rishi is watching a county maintenance crew mow the park across the street. He notices the mower takes 16 sec to pass through 60c of rotation from one end of the park to the other. If the corner of the park is 40 meter directly across the street from his house,  (i) How wide is the park?  (ii) How fast (in kmph) does the mower travel as it cuts the grass?
Asked by badakhsharda | 14 Apr, 2022, 08:57: AM
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CBSE 10 - Maths
The angle of elevation of the top of a tower from two points distant s and t from its foot are complementary. Prove that the height of the tower is √st.
Asked by naancysingh | 09 Apr, 2022, 07:07: PM
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CBSE 10 - Maths
a person standing on the bank of a river observes that the angle subtented by a tree on the opposite bank of 60 degree. when he retreates 20m from the bank he find the angle to be 30 degree . find the height of the tree and the bradth of the river
Asked by vy499292 | 23 Jan, 2022, 08:04: PM
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CBSE 10 - Maths
If two crows are sitting at a height of 15 m and 10 m on different trees vertically opposite to each other. They view a vaddi (an estable) on the ground at a angle of depression 45°and 60° respectively. They start at the same time and fly at the same speed along the shortest path to pick up the vadai.Which bird will succeed in it.?
Asked by urzashu7818 | 15 Jan, 2021, 12:52: PM
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CBSE 10 - Maths
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Asked by arindeep.singh | 02 Oct, 2020, 12:19: PM
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CBSE 10 - Maths
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Asked by arindeep.singh | 02 Oct, 2020, 12:19: PM
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CBSE 10 - Maths
the angle of elevation of a cloud from a point h metre above a lake is theta. the angle of depression of its reflection in the lake is 45 degree. Find the height of the cloud
Asked by arindeep.singh | 11 Sep, 2020, 02:41: PM
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CBSE 10 - Maths
a fire in the building Bis reported on telephone to two fire staitons P and Q, 20 km apart from each other on a straight road P observes that the fire is at an angle of 60 degree to the road and Q observes that it is at an angle of 45 degree to the road. What station should send its team and how much time will this team have to travel?
Asked by debeswar32 | 06 Aug, 2020, 10:55: AM
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CBSE 10 - Maths
from a point on the ground the angles of elevation of the bottom and top of a communication tower fixed on the top of a 20 meter high building a 45 degree and 60 degree respectivelyf.find the height of the tower.
Asked by ahmadaarif199 | 24 Jul, 2020, 02:58: PM
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