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Finding the Fourth Proportional to 856.69, 1,285.13 and 279.56

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Solution

The fourth proportional to 856.69, 1,285.13 and 279.56 is: 419.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.69 : 1,285.13 = 279.56 : x
  2. Step 2: Convert to fraction form
    856.69/1,285.13 = 279.56/x
  3. Step 3: Cross multiply
    856.69x = 1,285.13 × 279.56
  4. Step 4: Simplify right side
    856.69x = 359,274.85
  5. Step 5: Solve for x
    x = 359,274.85/856.69
  6. Step 6: Final answer
    x = 419.38

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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.