Finding the Fourth Proportional to 1,068.80, 1,595.50 and 990.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,068.80 : 1,595.50 = 990.63 : x
2. Step 2: Convert to fraction form
   1,068.80/1,595.50 = 990.63/x
3. Step 3: Cross multiply
   1,068.80x = 1,595.50 × 990.63
4. Step 4: Simplify right side
   1,068.80x = 1,580,547.69
5. Step 5: Solve for x
   x = 1,580,547.69/1,068.80
6. Step 6: Final answer
   x = 1,478.81