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Finding the Fourth Proportional to 1,221.36, 1,830.36 and 643.08

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Solution

The fourth proportional to 1,221.36, 1,830.36 and 643.08 is: 963.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.36 : 1,830.36 = 643.08 : x
  2. Step 2: Convert to fraction form
    1,221.36/1,830.36 = 643.08/x
  3. Step 3: Cross multiply
    1,221.36x = 1,830.36 × 643.08
  4. Step 4: Simplify right side
    1,221.36x = 1,177,067.91
  5. Step 5: Solve for x
    x = 1,177,067.91/1,221.36
  6. Step 6: Final answer
    x = 963.74

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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.