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Finding the Fourth Proportional to 656.80, 906.40 and 394.78

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Solution

The fourth proportional to 656.80, 906.40 and 394.78 is: 544.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.80 : 906.40 = 394.78 : x
  2. Step 2: Convert to fraction form
    656.80/906.40 = 394.78/x
  3. Step 3: Cross multiply
    656.80x = 906.40 × 394.78
  4. Step 4: Simplify right side
    656.80x = 357,828.59
  5. Step 5: Solve for x
    x = 357,828.59/656.80
  6. Step 6: Final answer
    x = 544.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.