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Finding the Fourth Proportional to 310.48, 465.40 and 139.28

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Solution

The fourth proportional to 310.48, 465.40 and 139.28 is: 208.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.48 : 465.40 = 139.28 : x
  2. Step 2: Convert to fraction form
    310.48/465.40 = 139.28/x
  3. Step 3: Cross multiply
    310.48x = 465.40 × 139.28
  4. Step 4: Simplify right side
    310.48x = 64,820.91
  5. Step 5: Solve for x
    x = 64,820.91/310.48
  6. Step 6: Final answer
    x = 208.78

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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.