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Finding the Fourth Proportional to 859.40, 1,288.45 and 426.86

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Solution

The fourth proportional to 859.40, 1,288.45 and 426.86 is: 639.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.40 : 1,288.45 = 426.86 : x
  2. Step 2: Convert to fraction form
    859.40/1,288.45 = 426.86/x
  3. Step 3: Cross multiply
    859.40x = 1,288.45 × 426.86
  4. Step 4: Simplify right side
    859.40x = 549,987.77
  5. Step 5: Solve for x
    x = 549,987.77/859.40
  6. Step 6: Final answer
    x = 639.97

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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.