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Finding the Fourth Proportional to 99.90, 149.12 and 87.75

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Solution

The fourth proportional to 99.90, 149.12 and 87.75 is: 130.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 149.12 = 87.75 : x
  2. Step 2: Convert to fraction form
    99.90/149.12 = 87.75/x
  3. Step 3: Cross multiply
    99.90x = 149.12 × 87.75
  4. Step 4: Simplify right side
    99.90x = 13,085.66
  5. Step 5: Solve for x
    x = 13,085.66/99.90
  6. Step 6: Final answer
    x = 130.99

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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.