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Finding the Fourth Proportional to 102.80, 141.78 and 71.77

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Solution

The fourth proportional to 102.80, 141.78 and 71.77 is: 98.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.80 : 141.78 = 71.77 : x
  2. Step 2: Convert to fraction form
    102.80/141.78 = 71.77/x
  3. Step 3: Cross multiply
    102.80x = 141.78 × 71.77
  4. Step 4: Simplify right side
    102.80x = 10,175.55
  5. Step 5: Solve for x
    x = 10,175.55/102.80
  6. Step 6: Final answer
    x = 98.98

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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.