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Finding the Fourth Proportional to 48.45, 72.20 and 42.78

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Solution

The fourth proportional to 48.45, 72.20 and 42.78 is: 63.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    48.45 : 72.20 = 42.78 : x
  2. Step 2: Convert to fraction form
    48.45/72.20 = 42.78/x
  3. Step 3: Cross multiply
    48.45x = 72.20 × 42.78
  4. Step 4: Simplify right side
    48.45x = 3,088.50
  5. Step 5: Solve for x
    x = 3,088.50/48.45
  6. Step 6: Final answer
    x = 63.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.