2+4+6+8...+222 berapa hasilnya? dan caranya

Barisan Aritmatika
2,4,6,8,...,222

n = (Un - a)/b + 1
n = (222-2)/2 + 1
n = 111

Sn = (n/2)(a + Un)
S111 = (111/2)(2 + 222)
S111 = 111 × 112
S111 = 12432