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Finding the Fourth Proportional to 642.50, 959.05 and 551.78

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Solution

The fourth proportional to 642.50, 959.05 and 551.78 is: 823.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.50 : 959.05 = 551.78 : x
  2. Step 2: Convert to fraction form
    642.50/959.05 = 551.78/x
  3. Step 3: Cross multiply
    642.50x = 959.05 × 551.78
  4. Step 4: Simplify right side
    642.50x = 529,184.61
  5. Step 5: Solve for x
    x = 529,184.61/642.50
  6. Step 6: Final answer
    x = 823.63

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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.