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Finding the Fourth Proportional to 390.66, 581.79 and 383.85

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Solution

The fourth proportional to 390.66, 581.79 and 383.85 is: 571.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.66 : 581.79 = 383.85 : x
  2. Step 2: Convert to fraction form
    390.66/581.79 = 383.85/x
  3. Step 3: Cross multiply
    390.66x = 581.79 × 383.85
  4. Step 4: Simplify right side
    390.66x = 223,320.09
  5. Step 5: Solve for x
    x = 223,320.09/390.66
  6. Step 6: Final answer
    x = 571.65

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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.