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Finding the Fourth Proportional to 820.50, 1,230.75 and 212.50

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Solution

The fourth proportional to 820.50, 1,230.75 and 212.50 is: 318.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.50 : 1,230.75 = 212.50 : x
  2. Step 2: Convert to fraction form
    820.50/1,230.75 = 212.50/x
  3. Step 3: Cross multiply
    820.50x = 1,230.75 × 212.50
  4. Step 4: Simplify right side
    820.50x = 261,534.38
  5. Step 5: Solve for x
    x = 261,534.38/820.50
  6. Step 6: Final answer
    x = 318.75

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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.