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Finding the Fourth Proportional to 312.81, 468.80 and 139.36

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Solution

The fourth proportional to 312.81, 468.80 and 139.36 is: 208.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.81 : 468.80 = 139.36 : x
  2. Step 2: Convert to fraction form
    312.81/468.80 = 139.36/x
  3. Step 3: Cross multiply
    312.81x = 468.80 × 139.36
  4. Step 4: Simplify right side
    312.81x = 65,331.97
  5. Step 5: Solve for x
    x = 65,331.97/312.81
  6. Step 6: Final answer
    x = 208.86

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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.