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Finding the Fourth Proportional to 270.40, 405.60 and 257.80

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Solution

The fourth proportional to 270.40, 405.60 and 257.80 is: 386.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    270.40 : 405.60 = 257.80 : x
  2. Step 2: Convert to fraction form
    270.40/405.60 = 257.80/x
  3. Step 3: Cross multiply
    270.40x = 405.60 × 257.80
  4. Step 4: Simplify right side
    270.40x = 104,563.68
  5. Step 5: Solve for x
    x = 104,563.68/270.40
  6. Step 6: Final answer
    x = 386.70

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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.