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Finding the Fourth Proportional to 1,291.40, 1,782.21 and 731.89

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Solution

The fourth proportional to 1,291.40, 1,782.21 and 731.89 is: 1,010.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291.40 : 1,782.21 = 731.89 : x
  2. Step 2: Convert to fraction form
    1,291.40/1,782.21 = 731.89/x
  3. Step 3: Cross multiply
    1,291.40x = 1,782.21 × 731.89
  4. Step 4: Simplify right side
    1,291.40x = 1,304,381.68
  5. Step 5: Solve for x
    x = 1,304,381.68/1,291.40
  6. Step 6: Final answer
    x = 1,010.05

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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.