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Finding the Fourth Proportional to 178.07, 245.78 and 128.86

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Solution

The fourth proportional to 178.07, 245.78 and 128.86 is: 177.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    178.07 : 245.78 = 128.86 : x
  2. Step 2: Convert to fraction form
    178.07/245.78 = 128.86/x
  3. Step 3: Cross multiply
    178.07x = 245.78 × 128.86
  4. Step 4: Simplify right side
    178.07x = 31,670.57
  5. Step 5: Solve for x
    x = 31,670.57/178.07
  6. Step 6: Final answer
    x = 177.86

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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.