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Finding the Fourth Proportional to 82.40, 113.72 and 64.92

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Solution

The fourth proportional to 82.40, 113.72 and 64.92 is: 89.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.40 : 113.72 = 64.92 : x
  2. Step 2: Convert to fraction form
    82.40/113.72 = 64.92/x
  3. Step 3: Cross multiply
    82.40x = 113.72 × 64.92
  4. Step 4: Simplify right side
    82.40x = 7,382.70
  5. Step 5: Solve for x
    x = 7,382.70/82.40
  6. Step 6: Final answer
    x = 89.60

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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.