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Finding the Fourth Proportional to 155.88, 215.12 and 86.88

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Solution

The fourth proportional to 155.88, 215.12 and 86.88 is: 119.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.88 : 215.12 = 86.88 : x
  2. Step 2: Convert to fraction form
    155.88/215.12 = 86.88/x
  3. Step 3: Cross multiply
    155.88x = 215.12 × 86.88
  4. Step 4: Simplify right side
    155.88x = 18,689.63
  5. Step 5: Solve for x
    x = 18,689.63/155.88
  6. Step 6: Final answer
    x = 119.90

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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.