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Finding the Fourth Proportional to 78.81, 117.36 and 76.98

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Solution

The fourth proportional to 78.81, 117.36 and 76.98 is: 114.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 117.36 = 76.98 : x
  2. Step 2: Convert to fraction form
    78.81/117.36 = 76.98/x
  3. Step 3: Cross multiply
    78.81x = 117.36 × 76.98
  4. Step 4: Simplify right side
    78.81x = 9,034.37
  5. Step 5: Solve for x
    x = 9,034.37/78.81
  6. Step 6: Final answer
    x = 114.63

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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.