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Finding the Fourth Proportional to 101.78, 140.53 and 65

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Solution

The fourth proportional to 101.78, 140.53 and 65 is: 89.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.78 : 140.53 = 65 : x
  2. Step 2: Convert to fraction form
    101.78/140.53 = 65/x
  3. Step 3: Cross multiply
    101.78x = 140.53 × 65
  4. Step 4: Simplify right side
    101.78x = 9,134.45
  5. Step 5: Solve for x
    x = 9,134.45/101.78
  6. Step 6: Final answer
    x = 89.75

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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.