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Finding the Fourth Proportional to 1,198.78, 1,798.99 and 429.28

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Solution

The fourth proportional to 1,198.78, 1,798.99 and 429.28 is: 644.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,198.78 : 1,798.99 = 429.28 : x
  2. Step 2: Convert to fraction form
    1,198.78/1,798.99 = 429.28/x
  3. Step 3: Cross multiply
    1,198.78x = 1,798.99 × 429.28
  4. Step 4: Simplify right side
    1,198.78x = 772,271.60
  5. Step 5: Solve for x
    x = 772,271.60/1,198.78
  6. Step 6: Final answer
    x = 644.21

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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.