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Finding the Fourth Proportional to 78.06, 117.09 and 65.28

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Solution

The fourth proportional to 78.06, 117.09 and 65.28 is: 97.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.06 : 117.09 = 65.28 : x
  2. Step 2: Convert to fraction form
    78.06/117.09 = 65.28/x
  3. Step 3: Cross multiply
    78.06x = 117.09 × 65.28
  4. Step 4: Simplify right side
    78.06x = 7,643.64
  5. Step 5: Solve for x
    x = 7,643.64/78.06
  6. Step 6: Final answer
    x = 97.92

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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.