Maths MC(need detailed steps)

1.) If four arithmatic means are inserted between 12 and 27,
then the sum of the four arithmatic means is
A. 78 B. 90 B. 105 D. 117
sol
(12+27)*(4+2)/2=117 (D)

2.) sin^2 1度 + sin^2 3度+sin^2 5度+...+sin^2 87度+sin^2 89度=

A. 22 B. 22.5 C. 44.5 D. 45
sol
A=sin^2 1度 + sin^2 3度+sin^2 5度+...+sin^2 87度+sin^2 89度
A=sin^2 89度 + sin^2 87度+sin^2 85度+...+sin^2 3度+sin^2 1度
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2A=1+1+1+1....+1=1*(89+1)/2=45
A=22.5 (B)