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Finding the Fourth Proportional to 405.12, 558.42 and 388.92

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Solution

The fourth proportional to 405.12, 558.42 and 388.92 is: 536.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.12 : 558.42 = 388.92 : x
  2. Step 2: Convert to fraction form
    405.12/558.42 = 388.92/x
  3. Step 3: Cross multiply
    405.12x = 558.42 × 388.92
  4. Step 4: Simplify right side
    405.12x = 217,180.71
  5. Step 5: Solve for x
    x = 217,180.71/405.12
  6. Step 6: Final answer
    x = 536.09

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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.