question_answer

A round balloon of radius r subtends an angle \[\alpha \] at the eye of the observer while the angle of elevation of its center is\[\beta \]. What is the height of the center of the balloon?

A)  \[r\,\,\sin \,\,\beta \,\,\sec \frac{\alpha }{2}\]        

B)  \[r\,\,\sin \,\,\beta \,\,cos\frac{\alpha }{2}\]

C)  \[r\,\,\sin \,\,\beta \,\,cosec\frac{\alpha }{2}\]       

D)  \[r\,\,\cos \,\,\beta \,\,cosec\frac{\alpha }{2}\]