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Finding the Fourth Proportional to 420.87, 580.50 and 279

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Solution

The fourth proportional to 420.87, 580.50 and 279 is: 384.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.87 : 580.50 = 279 : x
  2. Step 2: Convert to fraction form
    420.87/580.50 = 279/x
  3. Step 3: Cross multiply
    420.87x = 580.50 × 279
  4. Step 4: Simplify right side
    420.87x = 161,959.50
  5. Step 5: Solve for x
    x = 161,959.50/420.87
  6. Step 6: Final answer
    x = 384.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.