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Finding the Fourth Proportional to 280.15, 420.10 and 135.78

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Solution

The fourth proportional to 280.15, 420.10 and 135.78 is: 203.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.15 : 420.10 = 135.78 : x
  2. Step 2: Convert to fraction form
    280.15/420.10 = 135.78/x
  3. Step 3: Cross multiply
    280.15x = 420.10 × 135.78
  4. Step 4: Simplify right side
    280.15x = 57,041.18
  5. Step 5: Solve for x
    x = 57,041.18/280.15
  6. Step 6: Final answer
    x = 203.61

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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.