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Finding the Fourth Proportional to 42.40, 58.35 and 38.80

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Solution

The fourth proportional to 42.40, 58.35 and 38.80 is: 53.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.40 : 58.35 = 38.80 : x
  2. Step 2: Convert to fraction form
    42.40/58.35 = 38.80/x
  3. Step 3: Cross multiply
    42.40x = 58.35 × 38.80
  4. Step 4: Simplify right side
    42.40x = 2,263.98
  5. Step 5: Solve for x
    x = 2,263.98/42.40
  6. Step 6: Final answer
    x = 53.40

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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.