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Finding the Fourth Proportional to 856.78, 1,286.80 and 492.28

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Solution

The fourth proportional to 856.78, 1,286.80 and 492.28 is: 739.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.78 : 1,286.80 = 492.28 : x
  2. Step 2: Convert to fraction form
    856.78/1,286.80 = 492.28/x
  3. Step 3: Cross multiply
    856.78x = 1,286.80 × 492.28
  4. Step 4: Simplify right side
    856.78x = 633,465.90
  5. Step 5: Solve for x
    x = 633,465.90/856.78
  6. Step 6: Final answer
    x = 739.36

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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.