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Finding the Fourth Proportional to 858.40, 1,286.47 and 389.52

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Solution

The fourth proportional to 858.40, 1,286.47 and 389.52 is: 583.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.40 : 1,286.47 = 389.52 : x
  2. Step 2: Convert to fraction form
    858.40/1,286.47 = 389.52/x
  3. Step 3: Cross multiply
    858.40x = 1,286.47 × 389.52
  4. Step 4: Simplify right side
    858.40x = 501,105.79
  5. Step 5: Solve for x
    x = 501,105.79/858.40
  6. Step 6: Final answer
    x = 583.77

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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.