Four pairs of triangles are described below…

Four pairs of triangles are described below. In how many of the pairs must the two triangles be congruent?

1. Both have sides of $5\ \text{cm}$ and $6\ \text{cm}$ and an angle of $40^\circ$ that is not between those sides.

1. Both have angles of $40^\circ$ and $60^\circ$ and a $7\ \text{cm}$ side between those two angles.

1. Both have angles of $50^\circ$, $60^\circ$ and $70^\circ$.

1. Both have sides of $4\ \text{cm}$, $5\ \text{cm}$ and $6\ \text{cm}$.