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Finding the Fourth Proportional to 390.12, 580.94 and 385.81

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Solution

The fourth proportional to 390.12, 580.94 and 385.81 is: 574.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.12 : 580.94 = 385.81 : x
  2. Step 2: Convert to fraction form
    390.12/580.94 = 385.81/x
  3. Step 3: Cross multiply
    390.12x = 580.94 × 385.81
  4. Step 4: Simplify right side
    390.12x = 224,129.08
  5. Step 5: Solve for x
    x = 224,129.08/390.12
  6. Step 6: Final answer
    x = 574.51

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.