Finding the Fourth Proportional to 1,345.48, 1,856.70 and 821.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.48 : 1,856.70 = 821.56 : x
2. Step 2: Convert to fraction form
   1,345.48/1,856.70 = 821.56/x
3. Step 3: Cross multiply
   1,345.48x = 1,856.70 × 821.56
4. Step 4: Simplify right side
   1,345.48x = 1,525,390.45
5. Step 5: Solve for x
   x = 1,525,390.45/1,345.48
6. Step 6: Final answer
   x = 1,133.71