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Finding the Fourth Proportional to 421.92, 582.20 and 390.96

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Solution

The fourth proportional to 421.92, 582.20 and 390.96 is: 539.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.92 : 582.20 = 390.96 : x
  2. Step 2: Convert to fraction form
    421.92/582.20 = 390.96/x
  3. Step 3: Cross multiply
    421.92x = 582.20 × 390.96
  4. Step 4: Simplify right side
    421.92x = 227,616.91
  5. Step 5: Solve for x
    x = 227,616.91/421.92
  6. Step 6: Final answer
    x = 539.48

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1.5x scale

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.