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Finding the Fourth Proportional to 55.20, 82.80 and 40

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Solution

The fourth proportional to 55.20, 82.80 and 40 is: 60

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.20 : 82.80 = 40 : x
  2. Step 2: Convert to fraction form
    55.20/82.80 = 40/x
  3. Step 3: Cross multiply
    55.20x = 82.80 × 40
  4. Step 4: Simplify right side
    55.20x = 3,312
  5. Step 5: Solve for x
    x = 3,312/55.20
  6. Step 6: Final answer
    x = 60

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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.