# The First Term of an A. P. is 5 and the Common Difference is 4. Complete the Following Activity and Find the Sum of the First 12 Terms of the A. P. - Algebra

The first term of an A. P. is 5 and the common difference is 4. Complete the following activity and find the sum of the first 12 terms of the A. P.

a = 5, d = 4, s12 = ?
s_n = n/2 [ square ]
s_12 = 12/2 [10 +square]
= 6 × square
 =square

#### Solution

s_n = n/2 [ 2a +(n-1)d ]

s_12 = 12/2 [10 + 11 xx 4 ]

 =12/2[10+44]
= 6 ×54
 s_n= 324

Concept: Sum of First n Terms of an AP
Is there an error in this question or solution?