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Finding the Fourth Proportional to 859.60, 1,289.70 and 421.02

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Solution

The fourth proportional to 859.60, 1,289.70 and 421.02 is: 631.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.60 : 1,289.70 = 421.02 : x
  2. Step 2: Convert to fraction form
    859.60/1,289.70 = 421.02/x
  3. Step 3: Cross multiply
    859.60x = 1,289.70 × 421.02
  4. Step 4: Simplify right side
    859.60x = 542,989.49
  5. Step 5: Solve for x
    x = 542,989.49/859.60
  6. Step 6: Final answer
    x = 631.68

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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.