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Finding the Fourth Proportional to 420.28, 580.20 and 288.19

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Solution

The fourth proportional to 420.28, 580.20 and 288.19 is: 397.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.28 : 580.20 = 288.19 : x
  2. Step 2: Convert to fraction form
    420.28/580.20 = 288.19/x
  3. Step 3: Cross multiply
    420.28x = 580.20 × 288.19
  4. Step 4: Simplify right side
    420.28x = 167,207.84
  5. Step 5: Solve for x
    x = 167,207.84/420.28
  6. Step 6: Final answer
    x = 397.85

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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.