What is the measure of ∠ a in this quadrilateral?

30°

Step-by-step explanation:

The sum of the angles of a quadrilateral is 360°. You have 3 angles given, so can find the fourth using that fact. (The double arcs on angles B and C mean those angles are congruent. Same symbols are used to mark same-size angles.)

... 360° = A + B + C + D

... 360° = A + 115° + 115° + 100°

... 360° -330° = A = 30°

this is the formula: v = the value of investment at the end of the time period

p = the principal amount (the initial amount invested)

r = the annual interest rate

n = the annual frequency of compounding (how many times a year interest is added)

t = the number of years the money is invested

^ means raise to the power of