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Finding the Fourth Proportional to 103.45, 143.47 and 99.80

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Solution

The fourth proportional to 103.45, 143.47 and 99.80 is: 138.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.45 : 143.47 = 99.80 : x
  2. Step 2: Convert to fraction form
    103.45/143.47 = 99.80/x
  3. Step 3: Cross multiply
    103.45x = 143.47 × 99.80
  4. Step 4: Simplify right side
    103.45x = 14,318.42
  5. Step 5: Solve for x
    x = 14,318.42/103.45
  6. Step 6: Final answer
    x = 138.41

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.