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Finding the Fourth Proportional to 78.02, 116.28 and 77.39

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Solution

The fourth proportional to 78.02, 116.28 and 77.39 is: 115.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.02 : 116.28 = 77.39 : x
  2. Step 2: Convert to fraction form
    78.02/116.28 = 77.39/x
  3. Step 3: Cross multiply
    78.02x = 116.28 × 77.39
  4. Step 4: Simplify right side
    78.02x = 8,998.91
  5. Step 5: Solve for x
    x = 8,998.91/78.02
  6. Step 6: Final answer
    x = 115.34

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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.