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Finding the Fourth Proportional to 78.28, 108.16 and 65.98

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Solution

The fourth proportional to 78.28, 108.16 and 65.98 is: 91.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.28 : 108.16 = 65.98 : x
  2. Step 2: Convert to fraction form
    78.28/108.16 = 65.98/x
  3. Step 3: Cross multiply
    78.28x = 108.16 × 65.98
  4. Step 4: Simplify right side
    78.28x = 7,136.40
  5. Step 5: Solve for x
    x = 7,136.40/78.28
  6. Step 6: Final answer
    x = 91.17

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.