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Finding the Fourth Proportional to 1,281.78, 1,768.80 and 816

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Solution

The fourth proportional to 1,281.78, 1,768.80 and 816 is: 1,126.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.78 : 1,768.80 = 816 : x
  2. Step 2: Convert to fraction form
    1,281.78/1,768.80 = 816/x
  3. Step 3: Cross multiply
    1,281.78x = 1,768.80 × 816
  4. Step 4: Simplify right side
    1,281.78x = 1,443,340.80
  5. Step 5: Solve for x
    x = 1,443,340.80/1,281.78
  6. Step 6: Final answer
    x = 1,126.04

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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.