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Finding the Fourth Proportional to 78.14, 107.85 and 64.47

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Solution

The fourth proportional to 78.14, 107.85 and 64.47 is: 88.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.14 : 107.85 = 64.47 : x
  2. Step 2: Convert to fraction form
    78.14/107.85 = 64.47/x
  3. Step 3: Cross multiply
    78.14x = 107.85 × 64.47
  4. Step 4: Simplify right side
    78.14x = 6,953.74
  5. Step 5: Solve for x
    x = 6,953.74/78.14
  6. Step 6: Final answer
    x = 88.99

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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.