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Finding the Fourth Proportional to 405.12, 559.92 and 389.76

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Solution

The fourth proportional to 405.12, 559.92 and 389.76 is: 538.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.12 : 559.92 = 389.76 : x
  2. Step 2: Convert to fraction form
    405.12/559.92 = 389.76/x
  3. Step 3: Cross multiply
    405.12x = 559.92 × 389.76
  4. Step 4: Simplify right side
    405.12x = 218,234.42
  5. Step 5: Solve for x
    x = 218,234.42/405.12
  6. Step 6: Final answer
    x = 538.69

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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.