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Finding the Fourth Proportional to 143.30, 197.64 and 99.78

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Solution

The fourth proportional to 143.30, 197.64 and 99.78 is: 137.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.30 : 197.64 = 99.78 : x
  2. Step 2: Convert to fraction form
    143.30/197.64 = 99.78/x
  3. Step 3: Cross multiply
    143.30x = 197.64 × 99.78
  4. Step 4: Simplify right side
    143.30x = 19,720.52
  5. Step 5: Solve for x
    x = 19,720.52/143.30
  6. Step 6: Final answer
    x = 137.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.