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Finding the Fourth Proportional to 280.72, 387.19 and 215.11

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Solution

The fourth proportional to 280.72, 387.19 and 215.11 is: 296.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.72 : 387.19 = 215.11 : x
  2. Step 2: Convert to fraction form
    280.72/387.19 = 215.11/x
  3. Step 3: Cross multiply
    280.72x = 387.19 × 215.11
  4. Step 4: Simplify right side
    280.72x = 83,288.44
  5. Step 5: Solve for x
    x = 83,288.44/280.72
  6. Step 6: Final answer
    x = 296.70

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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.