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Finding the Fourth Proportional to 99.80, 149.72 and 54.20

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Solution

The fourth proportional to 99.80, 149.72 and 54.20 is: 81.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.80 : 149.72 = 54.20 : x
  2. Step 2: Convert to fraction form
    99.80/149.72 = 54.20/x
  3. Step 3: Cross multiply
    99.80x = 149.72 × 54.20
  4. Step 4: Simplify right side
    99.80x = 8,114.82
  5. Step 5: Solve for x
    x = 8,114.82/99.80
  6. Step 6: Final answer
    x = 81.31

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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.