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Finding the Fourth Proportional to 84.02, 126.66 and 78.45

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Solution

The fourth proportional to 84.02, 126.66 and 78.45 is: 118.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.02 : 126.66 = 78.45 : x
  2. Step 2: Convert to fraction form
    84.02/126.66 = 78.45/x
  3. Step 3: Cross multiply
    84.02x = 126.66 × 78.45
  4. Step 4: Simplify right side
    84.02x = 9,935.45
  5. Step 5: Solve for x
    x = 9,935.45/84.02
  6. Step 6: Final answer
    x = 118.25

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.