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Finding the Fourth Proportional to 215.28, 321.12 and 207.81

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Solution

The fourth proportional to 215.28, 321.12 and 207.81 is: 309.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.28 : 321.12 = 207.81 : x
  2. Step 2: Convert to fraction form
    215.28/321.12 = 207.81/x
  3. Step 3: Cross multiply
    215.28x = 321.12 × 207.81
  4. Step 4: Simplify right side
    215.28x = 66,731.95
  5. Step 5: Solve for x
    x = 66,731.95/215.28
  6. Step 6: Final answer
    x = 309.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.