Finding the Fourth Proportional to 1,397.32, 1,927.80 and 978.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.32 : 1,927.80 = 978.34 : x
2. Step 2: Convert to fraction form
   1,397.32/1,927.80 = 978.34/x
3. Step 3: Cross multiply
   1,397.32x = 1,927.80 × 978.34
4. Step 4: Simplify right side
   1,397.32x = 1,886,043.85
5. Step 5: Solve for x
   x = 1,886,043.85/1,397.32
6. Step 6: Final answer
   x = 1,349.76