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Finding the Fourth Proportional to 84.78, 126.36 and 66.42

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Solution

The fourth proportional to 84.78, 126.36 and 66.42 is: 99.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.78 : 126.36 = 66.42 : x
  2. Step 2: Convert to fraction form
    84.78/126.36 = 66.42/x
  3. Step 3: Cross multiply
    84.78x = 126.36 × 66.42
  4. Step 4: Simplify right side
    84.78x = 8,392.83
  5. Step 5: Solve for x
    x = 8,392.83/84.78
  6. Step 6: Final answer
    x = 99.00

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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.