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Finding the Fourth Proportional to 805.74, 1,215.51 and 781.17

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Solution

The fourth proportional to 805.74, 1,215.51 and 781.17 is: 1,178.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.74 : 1,215.51 = 781.17 : x
  2. Step 2: Convert to fraction form
    805.74/1,215.51 = 781.17/x
  3. Step 3: Cross multiply
    805.74x = 1,215.51 × 781.17
  4. Step 4: Simplify right side
    805.74x = 949,519.95
  5. Step 5: Solve for x
    x = 949,519.95/805.74
  6. Step 6: Final answer
    x = 1,178.44

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.