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Finding the Fourth Proportional to 390.88, 585.36 and 253.72

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Solution

The fourth proportional to 390.88, 585.36 and 253.72 is: 379.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.88 : 585.36 = 253.72 : x
  2. Step 2: Convert to fraction form
    390.88/585.36 = 253.72/x
  3. Step 3: Cross multiply
    390.88x = 585.36 × 253.72
  4. Step 4: Simplify right side
    390.88x = 148,517.54
  5. Step 5: Solve for x
    x = 148,517.54/390.88
  6. Step 6: Final answer
    x = 379.96

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.