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Finding the Fourth Proportional to 103.77, 155.68 and 85.45

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Solution

The fourth proportional to 103.77, 155.68 and 85.45 is: 128.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.77 : 155.68 = 85.45 : x
  2. Step 2: Convert to fraction form
    103.77/155.68 = 85.45/x
  3. Step 3: Cross multiply
    103.77x = 155.68 × 85.45
  4. Step 4: Simplify right side
    103.77x = 13,302.86
  5. Step 5: Solve for x
    x = 13,302.86/103.77
  6. Step 6: Final answer
    x = 128.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.