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Finding the Fourth Proportional to 155.80, 215.16 and 128.44

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Solution

The fourth proportional to 155.80, 215.16 and 128.44 is: 177.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.80 : 215.16 = 128.44 : x
  2. Step 2: Convert to fraction form
    155.80/215.16 = 128.44/x
  3. Step 3: Cross multiply
    155.80x = 215.16 × 128.44
  4. Step 4: Simplify right side
    155.80x = 27,635.15
  5. Step 5: Solve for x
    x = 27,635.15/155.80
  6. Step 6: Final answer
    x = 177.38

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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.