To find out how many tickets were sold for the Friday night performance, we can calculate 45 percent of the total tickets sold.
The total number of tickets sold is 900.
First, we convert 45 percent to a decimal:
\[ 45% = \frac{45}{100} = 0.45 \]
Now, we can calculate the number of tickets sold for the Friday night performance:
\[ \text{Tickets for Friday night} = 0.45 \times 900 \]
Calculating that:
\[ 0.45 \times 900 = 405 \]
So, the number of tickets sold for the Friday night performance is 405.
The answer is 405.