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Finding the Fourth Proportional to 156.05, 215.21 and 100.76

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Solution

The fourth proportional to 156.05, 215.21 and 100.76 is: 138.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.05 : 215.21 = 100.76 : x
  2. Step 2: Convert to fraction form
    156.05/215.21 = 100.76/x
  3. Step 3: Cross multiply
    156.05x = 215.21 × 100.76
  4. Step 4: Simplify right side
    156.05x = 21,682.98
  5. Step 5: Solve for x
    x = 21,682.98/156.05
  6. Step 6: Final answer
    x = 138.95

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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.