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Finding the Fourth Proportional to 781.90, 1,078.02 and 501.66

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Solution

The fourth proportional to 781.90, 1,078.02 and 501.66 is: 691.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.90 : 1,078.02 = 501.66 : x
  2. Step 2: Convert to fraction form
    781.90/1,078.02 = 501.66/x
  3. Step 3: Cross multiply
    781.90x = 1,078.02 × 501.66
  4. Step 4: Simplify right side
    781.90x = 540,799.51
  5. Step 5: Solve for x
    x = 540,799.51/781.90
  6. Step 6: Final answer
    x = 691.65

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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.