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Finding the Fourth Proportional to 858.55, 1,287.34 and 345.43

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Solution

The fourth proportional to 858.55, 1,287.34 and 345.43 is: 517.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.55 : 1,287.34 = 345.43 : x
  2. Step 2: Convert to fraction form
    858.55/1,287.34 = 345.43/x
  3. Step 3: Cross multiply
    858.55x = 1,287.34 × 345.43
  4. Step 4: Simplify right side
    858.55x = 444,685.86
  5. Step 5: Solve for x
    x = 444,685.86/858.55
  6. Step 6: Final answer
    x = 517.95

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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.