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Finding the Fourth Proportional to 807.78, 1,116.12 and 643.44

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Solution

The fourth proportional to 807.78, 1,116.12 and 643.44 is: 889.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.78 : 1,116.12 = 643.44 : x
  2. Step 2: Convert to fraction form
    807.78/1,116.12 = 643.44/x
  3. Step 3: Cross multiply
    807.78x = 1,116.12 × 643.44
  4. Step 4: Simplify right side
    807.78x = 718,156.25
  5. Step 5: Solve for x
    x = 718,156.25/807.78
  6. Step 6: Final answer
    x = 889.05

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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.