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Finding the Fourth Proportional to 853.31, 1,280.27 and 420.77

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Solution

The fourth proportional to 853.31, 1,280.27 and 420.77 is: 631.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.31 : 1,280.27 = 420.77 : x
  2. Step 2: Convert to fraction form
    853.31/1,280.27 = 420.77/x
  3. Step 3: Cross multiply
    853.31x = 1,280.27 × 420.77
  4. Step 4: Simplify right side
    853.31x = 538,703.46
  5. Step 5: Solve for x
    x = 538,703.46/853.31
  6. Step 6: Final answer
    x = 631.31

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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.