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Finding the Fourth Proportional to 156.11, 215.31 and 123.31

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Solution

The fourth proportional to 156.11, 215.31 and 123.31 is: 170.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.11 : 215.31 = 123.31 : x
  2. Step 2: Convert to fraction form
    156.11/215.31 = 123.31/x
  3. Step 3: Cross multiply
    156.11x = 215.31 × 123.31
  4. Step 4: Simplify right side
    156.11x = 26,548.80
  5. Step 5: Solve for x
    x = 26,548.80/156.11
  6. Step 6: Final answer
    x = 170.06

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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.