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Finding the Fourth Proportional to 89.70, 123.90 and 65.10

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Solution

The fourth proportional to 89.70, 123.90 and 65.10 is: 89.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.70 : 123.90 = 65.10 : x
  2. Step 2: Convert to fraction form
    89.70/123.90 = 65.10/x
  3. Step 3: Cross multiply
    89.70x = 123.90 × 65.10
  4. Step 4: Simplify right side
    89.70x = 8,065.89
  5. Step 5: Solve for x
    x = 8,065.89/89.70
  6. Step 6: Final answer
    x = 89.92

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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.