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Finding the Fourth Proportional to 854.34, 1,280.89 and 421.19

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Solution

The fourth proportional to 854.34, 1,280.89 and 421.19 is: 631.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.34 : 1,280.89 = 421.19 : x
  2. Step 2: Convert to fraction form
    854.34/1,280.89 = 421.19/x
  3. Step 3: Cross multiply
    854.34x = 1,280.89 × 421.19
  4. Step 4: Simplify right side
    854.34x = 539,498.06
  5. Step 5: Solve for x
    x = 539,498.06/854.34
  6. Step 6: Final answer
    x = 631.48

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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.