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Finding the Fourth Proportional to 257.40, 386.06 and 74.75

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Solution

The fourth proportional to 257.40, 386.06 and 74.75 is: 112.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.40 : 386.06 = 74.75 : x
  2. Step 2: Convert to fraction form
    257.40/386.06 = 74.75/x
  3. Step 3: Cross multiply
    257.40x = 386.06 × 74.75
  4. Step 4: Simplify right side
    257.40x = 28,858.12
  5. Step 5: Solve for x
    x = 28,858.12/257.40
  6. Step 6: Final answer
    x = 112.11

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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.