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Finding the Fourth Proportional to 891.09, 1,335.45 and 781.13

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Solution

The fourth proportional to 891.09, 1,335.45 and 781.13 is: 1,170.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.09 : 1,335.45 = 781.13 : x
  2. Step 2: Convert to fraction form
    891.09/1,335.45 = 781.13/x
  3. Step 3: Cross multiply
    891.09x = 1,335.45 × 781.13
  4. Step 4: Simplify right side
    891.09x = 1,043,153.38
  5. Step 5: Solve for x
    x = 1,043,153.38/891.09
  6. Step 6: Final answer
    x = 1,170.65

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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.