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Finding the Fourth Proportional to 102.90, 155.16 and 90.10

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Solution

The fourth proportional to 102.90, 155.16 and 90.10 is: 135.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.90 : 155.16 = 90.10 : x
  2. Step 2: Convert to fraction form
    102.90/155.16 = 90.10/x
  3. Step 3: Cross multiply
    102.90x = 155.16 × 90.10
  4. Step 4: Simplify right side
    102.90x = 13,979.47
  5. Step 5: Solve for x
    x = 13,979.47/102.90
  6. Step 6: Final answer
    x = 135.85

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.