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Finding the Fourth Proportional to 55, 75.90 and 39.50

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Solution

The fourth proportional to 55, 75.90 and 39.50 is: 54.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    55 : 75.90 = 39.50 : x
  2. Step 2: Convert to fraction form
    55/75.90 = 39.50/x
  3. Step 3: Cross multiply
    55x = 75.90 × 39.50
  4. Step 4: Simplify right side
    55x = 2,998.05
  5. Step 5: Solve for x
    x = 2,998.05/55
  6. Step 6: Final answer
    x = 54.51

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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.