30 what is the sum of this series?

Is the orthocenter of a triangle on the inside ?

The reflexive property of congruence lets you say that ∠pqr ≅

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.