In an arithmetic progression of 21 terms, the sum of the first 2 terms is −26 and that of the middle 3 is 75. Find the first term and the common difference. Hence, determine the total sum of the arithmetic progression.

Compare the cost of the bike trips from the two companies shown.for both the cost in a linear function of the number of days which statements is true

Solve the system of equations y= 3/2 - 1, -x+ y =-3

Given: ab ≅ cd and ad ≅ bc prove: abcd is a parallelogram. statements reasons 1. ab ≅ cd; ad ≅ bc 1. given 2. ac ≅ ac 2. reflexive property 3. △adc ≅ △cba 3. ? 4. ∠dac ≅ ∠bca; ∠acd ≅ ∠cab 4. cpctc 5. ∠dac and ∠bca are alt. int. ∠s; ∠acd and ∠cab are alt. int. ∠s 5. definition of alternate interior angles 6. ab ∥ cd; ad ∥ bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3? triangle angle sum theorem sas congruency theorem sss congruency theorem cpctc