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Finding the Fourth Proportional to 656.37, 905.39 and 390.71

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Solution

The fourth proportional to 656.37, 905.39 and 390.71 is: 538.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.37 : 905.39 = 390.71 : x
  2. Step 2: Convert to fraction form
    656.37/905.39 = 390.71/x
  3. Step 3: Cross multiply
    656.37x = 905.39 × 390.71
  4. Step 4: Simplify right side
    656.37x = 353,745.24
  5. Step 5: Solve for x
    x = 353,745.24/656.37
  6. Step 6: Final answer
    x = 538.94

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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.