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Finding the Fourth Proportional to 854.86, 1,281.48 and 421.54

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Solution

The fourth proportional to 854.86, 1,281.48 and 421.54 is: 631.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.86 : 1,281.48 = 421.54 : x
  2. Step 2: Convert to fraction form
    854.86/1,281.48 = 421.54/x
  3. Step 3: Cross multiply
    854.86x = 1,281.48 × 421.54
  4. Step 4: Simplify right side
    854.86x = 540,195.08
  5. Step 5: Solve for x
    x = 540,195.08/854.86
  6. Step 6: Final answer
    x = 631.91

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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.