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Finding the Fourth Proportional to 856.76, 1,284.02 and 387.89

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Solution

The fourth proportional to 856.76, 1,284.02 and 387.89 is: 581.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.76 : 1,284.02 = 387.89 : x
  2. Step 2: Convert to fraction form
    856.76/1,284.02 = 387.89/x
  3. Step 3: Cross multiply
    856.76x = 1,284.02 × 387.89
  4. Step 4: Simplify right side
    856.76x = 498,050.16
  5. Step 5: Solve for x
    x = 498,050.16/856.76
  6. Step 6: Final answer
    x = 581.32

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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.