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Finding the Fourth Proportional to 829.10, 1,243.65 and 621.20

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Solution

The fourth proportional to 829.10, 1,243.65 and 621.20 is: 931.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    829.10 : 1,243.65 = 621.20 : x
  2. Step 2: Convert to fraction form
    829.10/1,243.65 = 621.20/x
  3. Step 3: Cross multiply
    829.10x = 1,243.65 × 621.20
  4. Step 4: Simplify right side
    829.10x = 772,555.38
  5. Step 5: Solve for x
    x = 772,555.38/829.10
  6. Step 6: Final answer
    x = 931.80

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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.