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Finding the Fourth Proportional to 390.47, 585.34 and 253.11

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Solution

The fourth proportional to 390.47, 585.34 and 253.11 is: 379.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.47 : 585.34 = 253.11 : x
  2. Step 2: Convert to fraction form
    390.47/585.34 = 253.11/x
  3. Step 3: Cross multiply
    390.47x = 585.34 × 253.11
  4. Step 4: Simplify right side
    390.47x = 148,155.41
  5. Step 5: Solve for x
    x = 148,155.41/390.47
  6. Step 6: Final answer
    x = 379.43

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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.