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Finding the Fourth Proportional to 100.80, 151.20 and 99.20

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Solution

The fourth proportional to 100.80, 151.20 and 99.20 is: 148.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.80 : 151.20 = 99.20 : x
  2. Step 2: Convert to fraction form
    100.80/151.20 = 99.20/x
  3. Step 3: Cross multiply
    100.80x = 151.20 × 99.20
  4. Step 4: Simplify right side
    100.80x = 14,999.04
  5. Step 5: Solve for x
    x = 14,999.04/100.80
  6. Step 6: Final answer
    x = 148.80

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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.