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Finding the Fourth Proportional to 78.21, 116.73 and 76.68

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Solution

The fourth proportional to 78.21, 116.73 and 76.68 is: 114.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.21 : 116.73 = 76.68 : x
  2. Step 2: Convert to fraction form
    78.21/116.73 = 76.68/x
  3. Step 3: Cross multiply
    78.21x = 116.73 × 76.68
  4. Step 4: Simplify right side
    78.21x = 8,950.86
  5. Step 5: Solve for x
    x = 8,950.86/78.21
  6. Step 6: Final answer
    x = 114.45

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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.