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Finding the Fourth Proportional to 90.34, 135.70 and 87.09

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Solution

The fourth proportional to 90.34, 135.70 and 87.09 is: 130.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.34 : 135.70 = 87.09 : x
  2. Step 2: Convert to fraction form
    90.34/135.70 = 87.09/x
  3. Step 3: Cross multiply
    90.34x = 135.70 × 87.09
  4. Step 4: Simplify right side
    90.34x = 11,818.11
  5. Step 5: Solve for x
    x = 11,818.11/90.34
  6. Step 6: Final answer
    x = 130.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.