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Finding the Fourth Proportional to 66.58, 99.90 and 42.55

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Solution

The fourth proportional to 66.58, 99.90 and 42.55 is: 63.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.58 : 99.90 = 42.55 : x
  2. Step 2: Convert to fraction form
    66.58/99.90 = 42.55/x
  3. Step 3: Cross multiply
    66.58x = 99.90 × 42.55
  4. Step 4: Simplify right side
    66.58x = 4,250.75
  5. Step 5: Solve for x
    x = 4,250.75/66.58
  6. Step 6: Final answer
    x = 63.84

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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.