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Finding the Fourth Proportional to 78.30, 108.19 and 64.48

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Solution

The fourth proportional to 78.30, 108.19 and 64.48 is: 89.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.30 : 108.19 = 64.48 : x
  2. Step 2: Convert to fraction form
    78.30/108.19 = 64.48/x
  3. Step 3: Cross multiply
    78.30x = 108.19 × 64.48
  4. Step 4: Simplify right side
    78.30x = 6,976.09
  5. Step 5: Solve for x
    x = 6,976.09/78.30
  6. Step 6: Final answer
    x = 89.09

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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.