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Finding the Fourth Proportional to 99.20, 148.80 and 78.95

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Solution

The fourth proportional to 99.20, 148.80 and 78.95 is: 118.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.20 : 148.80 = 78.95 : x
  2. Step 2: Convert to fraction form
    99.20/148.80 = 78.95/x
  3. Step 3: Cross multiply
    99.20x = 148.80 × 78.95
  4. Step 4: Simplify right side
    99.20x = 11,748.43
  5. Step 5: Solve for x
    x = 11,748.43/99.20
  6. Step 6: Final answer
    x = 118.43

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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.