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Finding the Fourth Proportional to 66.10, 91.20 and 42.78

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Solution

The fourth proportional to 66.10, 91.20 and 42.78 is: 59.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.10 : 91.20 = 42.78 : x
  2. Step 2: Convert to fraction form
    66.10/91.20 = 42.78/x
  3. Step 3: Cross multiply
    66.10x = 91.20 × 42.78
  4. Step 4: Simplify right side
    66.10x = 3,902.04
  5. Step 5: Solve for x
    x = 3,902.04/66.10
  6. Step 6: Final answer
    x = 59.03

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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.