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Finding the Fourth Proportional to 156.11, 215.24 and 100.80

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Solution

The fourth proportional to 156.11, 215.24 and 100.80 is: 138.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.11 : 215.24 = 100.80 : x
  2. Step 2: Convert to fraction form
    156.11/215.24 = 100.80/x
  3. Step 3: Cross multiply
    156.11x = 215.24 × 100.80
  4. Step 4: Simplify right side
    156.11x = 21,695.69
  5. Step 5: Solve for x
    x = 21,695.69/156.11
  6. Step 6: Final answer
    x = 138.98

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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.