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Finding the Fourth Proportional to 680.64, 939.28 and 386

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Solution

The fourth proportional to 680.64, 939.28 and 386 is: 532.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.64 : 939.28 = 386 : x
  2. Step 2: Convert to fraction form
    680.64/939.28 = 386/x
  3. Step 3: Cross multiply
    680.64x = 939.28 × 386
  4. Step 4: Simplify right side
    680.64x = 362,562.08
  5. Step 5: Solve for x
    x = 362,562.08/680.64
  6. Step 6: Final answer
    x = 532.68

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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.