Finding the Fourth Proportional to 1,538.80, 2,123.52 and 840.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.80 : 2,123.52 = 840.16 : x
2. Step 2: Convert to fraction form
   1,538.80/2,123.52 = 840.16/x
3. Step 3: Cross multiply
   1,538.80x = 2,123.52 × 840.16
4. Step 4: Simplify right side
   1,538.80x = 1,784,096.56
5. Step 5: Solve for x
   x = 1,784,096.56/1,538.80
6. Step 6: Final answer
   x = 1,159.41