True or false Good luck! ceva's theorem can alway be used to determine wether or not medians of a triangle are concurrent.

ceva's theorem can always be used to determine whether or not altitudes of a triangle are concurrent.

in lobachevskian geometry, the sum of the angles of a triangle is less than 180 degrees

in riemannian geometry, the sum of the angles of a triangle is less than 180 degrees

in lobachevskian geometry, the summit angles of a saccheri quadrilateral are obtuse

in riemannian geometry, the summit angles of a saccheri quadrilateral are obtuse

in euclidian geometry, the summit angles of a saccheri quadrilateral are obtuse

in a circle, if an inscribed angle and a central angle intercept the same arc, which symbol (<,>,=) correctly completes this mathematical sentence?