Finding the Fourth Proportional to 1,415.78, 1,953.93 and 856.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,415.78 : 1,953.93 = 856.56 : x
2. Step 2: Convert to fraction form
   1,415.78/1,953.93 = 856.56/x
3. Step 3: Cross multiply
   1,415.78x = 1,953.93 × 856.56
4. Step 4: Simplify right side
   1,415.78x = 1,673,659.29
5. Step 5: Solve for x
   x = 1,673,659.29/1,415.78
6. Step 6: Final answer
   x = 1,182.14