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Finding the Fourth Proportional to 680.90, 939.63 and 386.17

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Solution

The fourth proportional to 680.90, 939.63 and 386.17 is: 532.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.90 : 939.63 = 386.17 : x
  2. Step 2: Convert to fraction form
    680.90/939.63 = 386.17/x
  3. Step 3: Cross multiply
    680.90x = 939.63 × 386.17
  4. Step 4: Simplify right side
    680.90x = 362,854.99
  5. Step 5: Solve for x
    x = 362,854.99/680.90
  6. Step 6: Final answer
    x = 532.90

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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.