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Finding the Fourth Proportional to 89.65, 123.70 and 65.09

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Solution

The fourth proportional to 89.65, 123.70 and 65.09 is: 89.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.65 : 123.70 = 65.09 : x
  2. Step 2: Convert to fraction form
    89.65/123.70 = 65.09/x
  3. Step 3: Cross multiply
    89.65x = 123.70 × 65.09
  4. Step 4: Simplify right side
    89.65x = 8,051.78
  5. Step 5: Solve for x
    x = 8,051.78/89.65
  6. Step 6: Final answer
    x = 89.82

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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.