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Finding the Fourth Proportional to 90.17, 134.51 and 87.69

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Solution

The fourth proportional to 90.17, 134.51 and 87.69 is: 130.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.17 : 134.51 = 87.69 : x
  2. Step 2: Convert to fraction form
    90.17/134.51 = 87.69/x
  3. Step 3: Cross multiply
    90.17x = 134.51 × 87.69
  4. Step 4: Simplify right side
    90.17x = 11,794.51
  5. Step 5: Solve for x
    x = 11,794.51/90.17
  6. Step 6: Final answer
    x = 130.81

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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.