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Finding the Fourth Proportional to 90.24, 134.64 and 86.88

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Solution

The fourth proportional to 90.24, 134.64 and 86.88 is: 129.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.24 : 134.64 = 86.88 : x
  2. Step 2: Convert to fraction form
    90.24/134.64 = 86.88/x
  3. Step 3: Cross multiply
    90.24x = 134.64 × 86.88
  4. Step 4: Simplify right side
    90.24x = 11,697.52
  5. Step 5: Solve for x
    x = 11,697.52/90.24
  6. Step 6: Final answer
    x = 129.63

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.