5,5:(2,2+1,78)=

To solve the expression \( 5.5 : (2.2 + 1.78) \), we first perform the addition inside the parentheses.

1. Calculate \( 2.2 + 1.78 \): \[ 2.2 + 1.78 = 4.98 \]

2. Now we calculate \( 5.5 : 4.98 \), which means \( 5.5 \div 4.98 \): \[ 5.5 \div 4.98 \approx 1.104 \]

Thus, the result of \( 5.5 : (2.2 + 1.78) \) is approximately \( 1.104 \).