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Finding the Fourth Proportional to 1,209.39, 1,668.86 and 816.95

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Solution

The fourth proportional to 1,209.39, 1,668.86 and 816.95 is: 1,127.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.39 : 1,668.86 = 816.95 : x
  2. Step 2: Convert to fraction form
    1,209.39/1,668.86 = 816.95/x
  3. Step 3: Cross multiply
    1,209.39x = 1,668.86 × 816.95
  4. Step 4: Simplify right side
    1,209.39x = 1,363,362.75
  5. Step 5: Solve for x
    x = 1,363,362.75/1,209.39
  6. Step 6: Final answer
    x = 1,127.31

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.