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Finding the Fourth Proportional to 420.57, 580.64 and 278.90

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Solution

The fourth proportional to 420.57, 580.64 and 278.90 is: 385.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.57 : 580.64 = 278.90 : x
  2. Step 2: Convert to fraction form
    420.57/580.64 = 278.90/x
  3. Step 3: Cross multiply
    420.57x = 580.64 × 278.90
  4. Step 4: Simplify right side
    420.57x = 161,942.64
  5. Step 5: Solve for x
    x = 161,942.64/420.57
  6. Step 6: Final answer
    x = 385.05

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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.