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Finding the Fourth Proportional to 89.40, 123.39 and 56.65

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Solution

The fourth proportional to 89.40, 123.39 and 56.65 is: 78.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.40 : 123.39 = 56.65 : x
  2. Step 2: Convert to fraction form
    89.40/123.39 = 56.65/x
  3. Step 3: Cross multiply
    89.40x = 123.39 × 56.65
  4. Step 4: Simplify right side
    89.40x = 6,990.04
  5. Step 5: Solve for x
    x = 6,990.04/89.40
  6. Step 6: Final answer
    x = 78.19

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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.