Find the measure of arc ec.
a) 50
b) 70
c) 100
d) 140

a) 50

Step-by-step explanation:

The angle formed by two chords is the average of the arc angles.

7x = (5x + 90) / 2

14x = 5x + 90

9x = 90

x = 10

So the measure of arc EC is 5x = 50°.

step-by-step explanation:

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560