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Finding the Fourth Proportional to 115.70, 159.50 and 78.77

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Solution

The fourth proportional to 115.70, 159.50 and 78.77 is: 108.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.70 : 159.50 = 78.77 : x
  2. Step 2: Convert to fraction form
    115.70/159.50 = 78.77/x
  3. Step 3: Cross multiply
    115.70x = 159.50 × 78.77
  4. Step 4: Simplify right side
    115.70x = 12,564.41
  5. Step 5: Solve for x
    x = 12,564.41/115.70
  6. Step 6: Final answer
    x = 108.60

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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.