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Finding the Fourth Proportional to 156.31, 215.75 and 90.86

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Solution

The fourth proportional to 156.31, 215.75 and 90.86 is: 125.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.31 : 215.75 = 90.86 : x
  2. Step 2: Convert to fraction form
    156.31/215.75 = 90.86/x
  3. Step 3: Cross multiply
    156.31x = 215.75 × 90.86
  4. Step 4: Simplify right side
    156.31x = 19,601.68
  5. Step 5: Solve for x
    x = 19,601.68/156.31
  6. Step 6: Final answer
    x = 125.40

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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.