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Finding the Fourth Proportional to 85.50, 117.90 and 76.77

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Solution

The fourth proportional to 85.50, 117.90 and 76.77 is: 105.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.50 : 117.90 = 76.77 : x
  2. Step 2: Convert to fraction form
    85.50/117.90 = 76.77/x
  3. Step 3: Cross multiply
    85.50x = 117.90 × 76.77
  4. Step 4: Simplify right side
    85.50x = 9,051.18
  5. Step 5: Solve for x
    x = 9,051.18/85.50
  6. Step 6: Final answer
    x = 105.86

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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.