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Finding the Fourth Proportional to 156.54, 215.55 and 138.80

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Solution

The fourth proportional to 156.54, 215.55 and 138.80 is: 191.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.54 : 215.55 = 138.80 : x
  2. Step 2: Convert to fraction form
    156.54/215.55 = 138.80/x
  3. Step 3: Cross multiply
    156.54x = 215.55 × 138.80
  4. Step 4: Simplify right side
    156.54x = 29,918.34
  5. Step 5: Solve for x
    x = 29,918.34/156.54
  6. Step 6: Final answer
    x = 191.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.