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Finding the Fourth Proportional to 78.78, 108.87 and 64.01

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Solution

The fourth proportional to 78.78, 108.87 and 64.01 is: 88.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.78 : 108.87 = 64.01 : x
  2. Step 2: Convert to fraction form
    78.78/108.87 = 64.01/x
  3. Step 3: Cross multiply
    78.78x = 108.87 × 64.01
  4. Step 4: Simplify right side
    78.78x = 6,968.22
  5. Step 5: Solve for x
    x = 6,968.22/78.78
  6. Step 6: Final answer
    x = 88.45

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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.