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Finding the Fourth Proportional to 99.90, 149.63 and 54.20

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Solution

The fourth proportional to 99.90, 149.63 and 54.20 is: 81.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 149.63 = 54.20 : x
  2. Step 2: Convert to fraction form
    99.90/149.63 = 54.20/x
  3. Step 3: Cross multiply
    99.90x = 149.63 × 54.20
  4. Step 4: Simplify right side
    99.90x = 8,110.05
  5. Step 5: Solve for x
    x = 8,110.05/99.90
  6. Step 6: Final answer
    x = 81.18

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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.