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Finding the Fourth Proportional to 99.80, 148.96 and 87.05

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Solution

The fourth proportional to 99.80, 148.96 and 87.05 is: 129.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.80 : 148.96 = 87.05 : x
  2. Step 2: Convert to fraction form
    99.80/148.96 = 87.05/x
  3. Step 3: Cross multiply
    99.80x = 148.96 × 87.05
  4. Step 4: Simplify right side
    99.80x = 12,966.97
  5. Step 5: Solve for x
    x = 12,966.97/99.80
  6. Step 6: Final answer
    x = 129.93

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.