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Finding the Fourth Proportional to 859.38, 1,289.45 and 420.51

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Solution

The fourth proportional to 859.38, 1,289.45 and 420.51 is: 630.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.38 : 1,289.45 = 420.51 : x
  2. Step 2: Convert to fraction form
    859.38/1,289.45 = 420.51/x
  3. Step 3: Cross multiply
    859.38x = 1,289.45 × 420.51
  4. Step 4: Simplify right side
    859.38x = 542,224.52
  5. Step 5: Solve for x
    x = 542,224.52/859.38
  6. Step 6: Final answer
    x = 630.95

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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.