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Finding the Fourth Proportional to 103.79, 143.20 and 64.45

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Solution

The fourth proportional to 103.79, 143.20 and 64.45 is: 88.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.79 : 143.20 = 64.45 : x
  2. Step 2: Convert to fraction form
    103.79/143.20 = 64.45/x
  3. Step 3: Cross multiply
    103.79x = 143.20 × 64.45
  4. Step 4: Simplify right side
    103.79x = 9,229.90
  5. Step 5: Solve for x
    x = 9,229.90/103.79
  6. Step 6: Final answer
    x = 88.93

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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.