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Finding the Fourth Proportional to 859.83, 1,289.13 and 421.21

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Solution

The fourth proportional to 859.83, 1,289.13 and 421.21 is: 631.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.83 : 1,289.13 = 421.21 : x
  2. Step 2: Convert to fraction form
    859.83/1,289.13 = 421.21/x
  3. Step 3: Cross multiply
    859.83x = 1,289.13 × 421.21
  4. Step 4: Simplify right side
    859.83x = 542,994.45
  5. Step 5: Solve for x
    x = 542,994.45/859.83
  6. Step 6: Final answer
    x = 631.51

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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.