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Finding the Fourth Proportional to 781.04, 1,165.79 and 688.80

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Solution

The fourth proportional to 781.04, 1,165.79 and 688.80 is: 1,028.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.04 : 1,165.79 = 688.80 : x
  2. Step 2: Convert to fraction form
    781.04/1,165.79 = 688.80/x
  3. Step 3: Cross multiply
    781.04x = 1,165.79 × 688.80
  4. Step 4: Simplify right side
    781.04x = 803,002.25
  5. Step 5: Solve for x
    x = 803,002.25/781.04
  6. Step 6: Final answer
    x = 1,028.12

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.