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Finding the Fourth Proportional to 859.78, 1,289.70 and 551.80

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Solution

The fourth proportional to 859.78, 1,289.70 and 551.80 is: 827.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.78 : 1,289.70 = 551.80 : x
  2. Step 2: Convert to fraction form
    859.78/1,289.70 = 551.80/x
  3. Step 3: Cross multiply
    859.78x = 1,289.70 × 551.80
  4. Step 4: Simplify right side
    859.78x = 711,656.46
  5. Step 5: Solve for x
    x = 711,656.46/859.78
  6. Step 6: Final answer
    x = 827.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.