Crazy mountains........................

At the foot of a mountain the elevation of its summit is ${ 45 }^{ \circ }$ ; after ascending $1000m$ towards the mountain up a slope of ${ 30 }^{ \circ }$ inclination , the elevation is found to be ${ 60 }^{ 0 }$ . Find the height of the mountain in km.

Note : Write answer till 4rth digit