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Finding the Fourth Proportional to 156.33, 215.82 and 128.79

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Solution

The fourth proportional to 156.33, 215.82 and 128.79 is: 177.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.33 : 215.82 = 128.79 : x
  2. Step 2: Convert to fraction form
    156.33/215.82 = 128.79/x
  3. Step 3: Cross multiply
    156.33x = 215.82 × 128.79
  4. Step 4: Simplify right side
    156.33x = 27,795.46
  5. Step 5: Solve for x
    x = 27,795.46/156.33
  6. Step 6: Final answer
    x = 177.80

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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.