In circle B, m ∠DBF = 75o, mFC =60°, and DE and AC are diameters.

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.

2. x2 + 8x + 12 = 0 to prove: x = -6 or x = -2