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Finding the Fourth Proportional to 257.28, 386.21 and 135.51

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Solution

The fourth proportional to 257.28, 386.21 and 135.51 is: 203.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 386.21 = 135.51 : x
  2. Step 2: Convert to fraction form
    257.28/386.21 = 135.51/x
  3. Step 3: Cross multiply
    257.28x = 386.21 × 135.51
  4. Step 4: Simplify right side
    257.28x = 52,332.71
  5. Step 5: Solve for x
    x = 52,332.71/257.28
  6. Step 6: Final answer
    x = 203.41

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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.