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Finding the Fourth Proportional to 83.65, 115.42 and 64.21

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Solution

The fourth proportional to 83.65, 115.42 and 64.21 is: 88.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.65 : 115.42 = 64.21 : x
  2. Step 2: Convert to fraction form
    83.65/115.42 = 64.21/x
  3. Step 3: Cross multiply
    83.65x = 115.42 × 64.21
  4. Step 4: Simplify right side
    83.65x = 7,411.12
  5. Step 5: Solve for x
    x = 7,411.12/83.65
  6. Step 6: Final answer
    x = 88.60

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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.