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Finding the Fourth Proportional to 156.31, 215.69 and 107.21

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Solution

The fourth proportional to 156.31, 215.69 and 107.21 is: 147.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.31 : 215.69 = 107.21 : x
  2. Step 2: Convert to fraction form
    156.31/215.69 = 107.21/x
  3. Step 3: Cross multiply
    156.31x = 215.69 × 107.21
  4. Step 4: Simplify right side
    156.31x = 23,124.13
  5. Step 5: Solve for x
    x = 23,124.13/156.31
  6. Step 6: Final answer
    x = 147.94

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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.