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Finding the Fourth Proportional to 280.72, 420.28 and 253.20

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Solution

The fourth proportional to 280.72, 420.28 and 253.20 is: 379.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.72 : 420.28 = 253.20 : x
  2. Step 2: Convert to fraction form
    280.72/420.28 = 253.20/x
  3. Step 3: Cross multiply
    280.72x = 420.28 × 253.20
  4. Step 4: Simplify right side
    280.72x = 106,414.90
  5. Step 5: Solve for x
    x = 106,414.90/280.72
  6. Step 6: Final answer
    x = 379.08

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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.