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Finding the Fourth Proportional to 407.76, 611.40 and 215.28

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Solution

The fourth proportional to 407.76, 611.40 and 215.28 is: 322.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.76 : 611.40 = 215.28 : x
  2. Step 2: Convert to fraction form
    407.76/611.40 = 215.28/x
  3. Step 3: Cross multiply
    407.76x = 611.40 × 215.28
  4. Step 4: Simplify right side
    407.76x = 131,622.19
  5. Step 5: Solve for x
    x = 131,622.19/407.76
  6. Step 6: Final answer
    x = 322.79

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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.