d = 3 , a₁₂ = 40 and S
= 7775
In an arithmetic sequence the nth term and sum to n terms are
<h3>• a

= a₁ + (n-1)d</h3><h3>• S

=

[2a + (n-1)d]</h3><h3>
where d is the common difference</h3><h3>a₆ = a₁ + 5d = 22 ⇒ 7 + 5d = 22 ⇒ 5d = 15 ⇔ d = 3</h3><h3>a₁₂ = 7 + 11d = 7 +( 11× 3) = 7 + 33 = 40</h3><h3>S₁₀₀ =

[(2×7) +(99×3)</h3><h3> = 25(14 + 297) = 25(311)= 7775</h3>
Answer:
The value of a is 50°.
Step-by-step explanation:
In an isosceles triangle, 2 sides have the same lengths and same angles so we can assume that the other side of the triangle is 65°.
Given that the total angle of a triangle is 180°, so have to subtract it :



Answer:
Step-by-step explanation:
Each term of the given arithmetic sequence is 6 more than the previous one. Thus, the next term is 26+6, or 32.
a(n) = 8 + 6(n-1)