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Finding the Fourth Proportional to 420.11, 580.24 and 280

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Solution

The fourth proportional to 420.11, 580.24 and 280 is: 386.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.11 : 580.24 = 280 : x
  2. Step 2: Convert to fraction form
    420.11/580.24 = 280/x
  3. Step 3: Cross multiply
    420.11x = 580.24 × 280
  4. Step 4: Simplify right side
    420.11x = 162,467.90
  5. Step 5: Solve for x
    x = 162,467.90/420.11
  6. Step 6: Final answer
    x = 386.72

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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.