By the definition of a ▱, ad∥bc and ab∥dc. using, ad as a transversal, ∠a and ∠ are same-side interior angles, so they are . using side as a transversal, ∠b and ∠c are same-side interior angles, so they are supplementary. using ab as a transversal, ∠a and ∠b are same-side interior angles, so they are supplementary. therefore, ∠a is congruent to ∠c because they are supplements of the same angle. similarly, ∠b is congruent to ∠.

the final price would be 29.6925

step-by-step explanation:

39.59 minus 25% equals 29.6925

overpriced

step-by-step explanation:

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for