Restate each of the following assertions in ‘‘if…, then…’’ form. (a) Perpendicular lines must…

Restate each of the following assertions in ‘‘if…, then…’’ form. (a) Perpendicular lines must intersect. (b) Any two great circles on S2 intersect. (c) Congruent triangles are similar. (d) Every triangle has angle sum less than or equal to 180_.