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Finding the Fourth Proportional to 47.80, 65.90 and 39.50

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Solution

The fourth proportional to 47.80, 65.90 and 39.50 is: 54.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.80 : 65.90 = 39.50 : x
  2. Step 2: Convert to fraction form
    47.80/65.90 = 39.50/x
  3. Step 3: Cross multiply
    47.80x = 65.90 × 39.50
  4. Step 4: Simplify right side
    47.80x = 2,602.52
  5. Step 5: Solve for x
    x = 2,602.52/47.80
  6. Step 6: Final answer
    x = 54.45

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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.