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Finding the Fourth Proportional to 67.64, 100.78 and 66.98

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Solution

The fourth proportional to 67.64, 100.78 and 66.98 is: 99.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.64 : 100.78 = 66.98 : x
  2. Step 2: Convert to fraction form
    67.64/100.78 = 66.98/x
  3. Step 3: Cross multiply
    67.64x = 100.78 × 66.98
  4. Step 4: Simplify right side
    67.64x = 6,750.24
  5. Step 5: Solve for x
    x = 6,750.24/67.64
  6. Step 6: Final answer
    x = 99.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.