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Finding the Fourth Proportional to 856.98, 1,285.79 and 279.86

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Solution

The fourth proportional to 856.98, 1,285.79 and 279.86 is: 419.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.98 : 1,285.79 = 279.86 : x
  2. Step 2: Convert to fraction form
    856.98/1,285.79 = 279.86/x
  3. Step 3: Cross multiply
    856.98x = 1,285.79 × 279.86
  4. Step 4: Simplify right side
    856.98x = 359,833.36
  5. Step 5: Solve for x
    x = 359,833.36/856.98
  6. Step 6: Final answer
    x = 419.89

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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.