Lines ℓ and m are intersected by transversal t. ℓ ∥ m. There are two parallel horizontal lines l and m intersected by another line t making angles 1 and 3 with l and 5, 7 with m. 1 ,4 and 2 , 3 are opposite angles at the point of intersection of l and t. 5, 8 and 6, 7 are opposite angles at the point of intersection of m and t.

If m∠3 = 78°, what is m∠6?

m∠6 =

°