Start overline, A, C, end overline are diameters of circle
P
PP.

Given:

m∠APB = 19°

To find:

The arc measure of DBC.

Solution:

∠APB and ∠DPC are vertical angles.

By vertical angle theorem:

m∠APB = m∠DPC

m∠DPC = 19°

DB is the diameter of the circle.

Angle measure of diameter = 180°

m∠DPB = 180°

m∠DPC + m∠CPB = m∠DPB

19° + m∠CPB = 180°

Subtract 19° from both sides.

19° + m∠CPB - 19° = 180° - 19°

m∠CPB = 161°

The measure of central angle is equal to the measure of intercepted arc.

m∠CPB = m(ar CPB)

m(ar CPB) = 161°

The arc measure of DBC is 161°.

cant open file sorry!

step-by-step explanation:

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.