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Finding the Fourth Proportional to 680.70, 939.40 and 386

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Solution

The fourth proportional to 680.70, 939.40 and 386 is: 532.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.70 : 939.40 = 386 : x
  2. Step 2: Convert to fraction form
    680.70/939.40 = 386/x
  3. Step 3: Cross multiply
    680.70x = 939.40 × 386
  4. Step 4: Simplify right side
    680.70x = 362,608.40
  5. Step 5: Solve for x
    x = 362,608.40/680.70
  6. Step 6: Final answer
    x = 532.70

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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.