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Finding the Fourth Proportional to 393.68, 590.40 and 257.45

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Solution

The fourth proportional to 393.68, 590.40 and 257.45 is: 386.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.68 : 590.40 = 257.45 : x
  2. Step 2: Convert to fraction form
    393.68/590.40 = 257.45/x
  3. Step 3: Cross multiply
    393.68x = 590.40 × 257.45
  4. Step 4: Simplify right side
    393.68x = 151,998.48
  5. Step 5: Solve for x
    x = 151,998.48/393.68
  6. Step 6: Final answer
    x = 386.10

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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.