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Finding the Fourth Proportional to 780.57, 1,078.10 and 518.13

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Solution

The fourth proportional to 780.57, 1,078.10 and 518.13 is: 715.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.57 : 1,078.10 = 518.13 : x
  2. Step 2: Convert to fraction form
    780.57/1,078.10 = 518.13/x
  3. Step 3: Cross multiply
    780.57x = 1,078.10 × 518.13
  4. Step 4: Simplify right side
    780.57x = 558,593.36
  5. Step 5: Solve for x
    x = 558,593.36/780.57
  6. Step 6: Final answer
    x = 715.62

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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.