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Finding the Fourth Proportional to 780.61, 1,076.91 and 500.76

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Solution

The fourth proportional to 780.61, 1,076.91 and 500.76 is: 690.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.61 : 1,076.91 = 500.76 : x
  2. Step 2: Convert to fraction form
    780.61/1,076.91 = 500.76/x
  3. Step 3: Cross multiply
    780.61x = 1,076.91 × 500.76
  4. Step 4: Simplify right side
    780.61x = 539,268.07
  5. Step 5: Solve for x
    x = 539,268.07/780.61
  6. Step 6: Final answer
    x = 690.83

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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.