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Finding the Fourth Proportional to 78.90, 118.40 and 65.49

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Solution

The fourth proportional to 78.90, 118.40 and 65.49 is: 98.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.90 : 118.40 = 65.49 : x
  2. Step 2: Convert to fraction form
    78.90/118.40 = 65.49/x
  3. Step 3: Cross multiply
    78.90x = 118.40 × 65.49
  4. Step 4: Simplify right side
    78.90x = 7,753.69
  5. Step 5: Solve for x
    x = 7,753.69/78.90
  6. Step 6: Final answer
    x = 98.27

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.