ABCD is a rhombus such that `angle ACB=40^(@). " Find " angle ADB.`
A
`20^@`
B
`30^@`
C
`50^@`
D
`40^@`
Text Solution
Verified by Experts
The correct Answer is:
C
Let the diagonals AC and BD intersect at O. Then , `angle BOC = 90^(@). " " [ therefore " diagonals of a rhombus intersect at right angles"]` In `triangle BOC,` we have `angle OCB + angle BOC+angle CBO=180^(@) " " ("sum of "angle " of a " triangle)` `rArr 40^(@) +90^(@)+angle CBO =180^(@) rArr angle CBO =50^(@).` Now, `angle ADB = angle CBO =50^(@) " " ("alt. interior " angle )`.
