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Finding the Fourth Proportional to 109.78, 164.35 and 77.07

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Solution

The fourth proportional to 109.78, 164.35 and 77.07 is: 115.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.78 : 164.35 = 77.07 : x
  2. Step 2: Convert to fraction form
    109.78/164.35 = 77.07/x
  3. Step 3: Cross multiply
    109.78x = 164.35 × 77.07
  4. Step 4: Simplify right side
    109.78x = 12,666.45
  5. Step 5: Solve for x
    x = 12,666.45/109.78
  6. Step 6: Final answer
    x = 115.38

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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.