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Finding the Fourth Proportional to 43.18, 64.80 and 31.20

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Solution

The fourth proportional to 43.18, 64.80 and 31.20 is: 46.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    43.18 : 64.80 = 31.20 : x
  2. Step 2: Convert to fraction form
    43.18/64.80 = 31.20/x
  3. Step 3: Cross multiply
    43.18x = 64.80 × 31.20
  4. Step 4: Simplify right side
    43.18x = 2,021.76
  5. Step 5: Solve for x
    x = 2,021.76/43.18
  6. Step 6: Final answer
    x = 46.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.