1.

Let ABC be a triangle in which the line joining the circumecentre and incentre is parallel to base BC of the triangle. Then answer the following questions : Then range of angle A is

Answer»

`[(pi)/(6),(pi)/(3)]`
`[(pi)/(3),(pi)/(2))`
`[(pi)/(3),(2pi)/(3)]={(pi)/(3)}`
`[0,(pi)/(2)]`

SOLUTION :
`because` The line joining O and I is parallel to BC
`therefore OI = DE` and OD = IE
OD = R COS A, IE = r
`therefore cos A = (r )/(R ) le (1)/(2)`
`rArr 0 lt cos A le (1)/(2)rArr (pi)/(3)le A lt (pi)/(2)`


Discussion

No Comment Found

Related InterviewSolutions