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Finding the Fourth Proportional to 421.92, 581.76 and 318.24

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Solution

The fourth proportional to 421.92, 581.76 and 318.24 is: 438.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.92 : 581.76 = 318.24 : x
  2. Step 2: Convert to fraction form
    421.92/581.76 = 318.24/x
  3. Step 3: Cross multiply
    421.92x = 581.76 × 318.24
  4. Step 4: Simplify right side
    421.92x = 185,139.30
  5. Step 5: Solve for x
    x = 185,139.30/421.92
  6. Step 6: Final answer
    x = 438.80

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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.