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Finding the Fourth Proportional to 42, 57.60 and 40.20

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Solution

The fourth proportional to 42, 57.60 and 40.20 is: 55.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    42 : 57.60 = 40.20 : x
  2. Step 2: Convert to fraction form
    42/57.60 = 40.20/x
  3. Step 3: Cross multiply
    42x = 57.60 × 40.20
  4. Step 4: Simplify right side
    42x = 2,315.52
  5. Step 5: Solve for x
    x = 2,315.52/42
  6. Step 6: Final answer
    x = 55.13

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.