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Finding the Fourth Proportional to 390.64, 586.92 and 219.76

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Solution

The fourth proportional to 390.64, 586.92 and 219.76 is: 330.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 586.92 = 219.76 : x
  2. Step 2: Convert to fraction form
    390.64/586.92 = 219.76/x
  3. Step 3: Cross multiply
    390.64x = 586.92 × 219.76
  4. Step 4: Simplify right side
    390.64x = 128,981.54
  5. Step 5: Solve for x
    x = 128,981.54/390.64
  6. Step 6: Final answer
    x = 330.18

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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.