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Finding the Fourth Proportional to 856.81, 1,287.20 and 492.49

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Solution

The fourth proportional to 856.81, 1,287.20 and 492.49 is: 739.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.81 : 1,287.20 = 492.49 : x
  2. Step 2: Convert to fraction form
    856.81/1,287.20 = 492.49/x
  3. Step 3: Cross multiply
    856.81x = 1,287.20 × 492.49
  4. Step 4: Simplify right side
    856.81x = 633,933.13
  5. Step 5: Solve for x
    x = 633,933.13/856.81
  6. Step 6: Final answer
    x = 739.88

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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.