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Finding the Fourth Proportional to 856.39, 1,284.31 and 279.13

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Solution

The fourth proportional to 856.39, 1,284.31 and 279.13 is: 418.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.39 : 1,284.31 = 279.13 : x
  2. Step 2: Convert to fraction form
    856.39/1,284.31 = 279.13/x
  3. Step 3: Cross multiply
    856.39x = 1,284.31 × 279.13
  4. Step 4: Simplify right side
    856.39x = 358,481.63
  5. Step 5: Solve for x
    x = 358,481.63/856.39
  6. Step 6: Final answer
    x = 418.60

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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.