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Finding the Fourth Proportional to 103.69, 142.99 and 64.90

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Solution

The fourth proportional to 103.69, 142.99 and 64.90 is: 89.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.69 : 142.99 = 64.90 : x
  2. Step 2: Convert to fraction form
    103.69/142.99 = 64.90/x
  3. Step 3: Cross multiply
    103.69x = 142.99 × 64.90
  4. Step 4: Simplify right side
    103.69x = 9,280.05
  5. Step 5: Solve for x
    x = 9,280.05/103.69
  6. Step 6: Final answer
    x = 89.50

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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.