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Finding the Fourth Proportional to 99.80, 149.60 and 85.32

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Solution

The fourth proportional to 99.80, 149.60 and 85.32 is: 127.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.80 : 149.60 = 85.32 : x
  2. Step 2: Convert to fraction form
    99.80/149.60 = 85.32/x
  3. Step 3: Cross multiply
    99.80x = 149.60 × 85.32
  4. Step 4: Simplify right side
    99.80x = 12,763.45
  5. Step 5: Solve for x
    x = 12,763.45/99.80
  6. Step 6: Final answer
    x = 127.90

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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.