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Finding the Fourth Proportional to 859.37, 1,290.56 and 640.05

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Solution

The fourth proportional to 859.37, 1,290.56 and 640.05 is: 961.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.37 : 1,290.56 = 640.05 : x
  2. Step 2: Convert to fraction form
    859.37/1,290.56 = 640.05/x
  3. Step 3: Cross multiply
    859.37x = 1,290.56 × 640.05
  4. Step 4: Simplify right side
    859.37x = 826,024.53
  5. Step 5: Solve for x
    x = 826,024.53/859.37
  6. Step 6: Final answer
    x = 961.20

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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.