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Finding the Fourth Proportional to 54.90, 75.78 and 42.60

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Solution

The fourth proportional to 54.90, 75.78 and 42.60 is: 58.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.90 : 75.78 = 42.60 : x
  2. Step 2: Convert to fraction form
    54.90/75.78 = 42.60/x
  3. Step 3: Cross multiply
    54.90x = 75.78 × 42.60
  4. Step 4: Simplify right side
    54.90x = 3,228.23
  5. Step 5: Solve for x
    x = 3,228.23/54.90
  6. Step 6: Final answer
    x = 58.80

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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.