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Finding the Fourth Proportional to 208.16, 312.34 and 139.71

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Solution

The fourth proportional to 208.16, 312.34 and 139.71 is: 209.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.16 : 312.34 = 139.71 : x
  2. Step 2: Convert to fraction form
    208.16/312.34 = 139.71/x
  3. Step 3: Cross multiply
    208.16x = 312.34 × 139.71
  4. Step 4: Simplify right side
    208.16x = 43,637.02
  5. Step 5: Solve for x
    x = 43,637.02/208.16
  6. Step 6: Final answer
    x = 209.63

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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.