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Finding the Fourth Proportional to 390.64, 538.54 and 279.92

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Solution

The fourth proportional to 390.64, 538.54 and 279.92 is: 385.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 538.54 = 279.92 : x
  2. Step 2: Convert to fraction form
    390.64/538.54 = 279.92/x
  3. Step 3: Cross multiply
    390.64x = 538.54 × 279.92
  4. Step 4: Simplify right side
    390.64x = 150,745.42
  5. Step 5: Solve for x
    x = 150,745.42/390.64
  6. Step 6: Final answer
    x = 385.89

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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.