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Finding the Fourth Proportional to 83.70, 115.43 and 78.57

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Solution

The fourth proportional to 83.70, 115.43 and 78.57 is: 108.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.70 : 115.43 = 78.57 : x
  2. Step 2: Convert to fraction form
    83.70/115.43 = 78.57/x
  3. Step 3: Cross multiply
    83.70x = 115.43 × 78.57
  4. Step 4: Simplify right side
    83.70x = 9,068.94
  5. Step 5: Solve for x
    x = 9,068.94/83.70
  6. Step 6: Final answer
    x = 108.35

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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.