according to intersecting chord theorem: The measure of the angle formed by two chords that intersect inside the circle is the sum of the chords' intercepted arcs.
m∠BPD = (M∠BD + M∠CA)
= (70 + 170)
= (240)
m∠BPD = 120
We know that a circle has a total of 360° around the center of circle. To find the measure of the remaining measure of angle of arcs, subtract them from the whole that is 360°