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Finding the Fourth Proportional to 38.40, 53 and 31.12

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Solution

The fourth proportional to 38.40, 53 and 31.12 is: 42.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.40 : 53 = 31.12 : x
  2. Step 2: Convert to fraction form
    38.40/53 = 31.12/x
  3. Step 3: Cross multiply
    38.40x = 53 × 31.12
  4. Step 4: Simplify right side
    38.40x = 1,649.36
  5. Step 5: Solve for x
    x = 1,649.36/38.40
  6. Step 6: Final answer
    x = 42.95

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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.