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Finding the Fourth Proportional to 280.78, 420.78 and 219.63

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Solution

The fourth proportional to 280.78, 420.78 and 219.63 is: 329.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.78 : 420.78 = 219.63 : x
  2. Step 2: Convert to fraction form
    280.78/420.78 = 219.63/x
  3. Step 3: Cross multiply
    280.78x = 420.78 × 219.63
  4. Step 4: Simplify right side
    280.78x = 92,415.91
  5. Step 5: Solve for x
    x = 92,415.91/280.78
  6. Step 6: Final answer
    x = 329.14

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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.