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Finding the Fourth Proportional to 824.16, 1,234.64 and 390.72

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Solution

The fourth proportional to 824.16, 1,234.64 and 390.72 is: 585.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    824.16 : 1,234.64 = 390.72 : x
  2. Step 2: Convert to fraction form
    824.16/1,234.64 = 390.72/x
  3. Step 3: Cross multiply
    824.16x = 1,234.64 × 390.72
  4. Step 4: Simplify right side
    824.16x = 482,398.54
  5. Step 5: Solve for x
    x = 482,398.54/824.16
  6. Step 6: Final answer
    x = 585.32

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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.