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Finding the Fourth Proportional to 781.71, 1,177.93 and 647.76

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Solution

The fourth proportional to 781.71, 1,177.93 and 647.76 is: 976.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.71 : 1,177.93 = 647.76 : x
  2. Step 2: Convert to fraction form
    781.71/1,177.93 = 647.76/x
  3. Step 3: Cross multiply
    781.71x = 1,177.93 × 647.76
  4. Step 4: Simplify right side
    781.71x = 763,015.94
  5. Step 5: Solve for x
    x = 763,015.94/781.71
  6. Step 6: Final answer
    x = 976.09

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.