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Finding the Fourth Proportional to 731.40, 1,009.34 and 399.84

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Solution

The fourth proportional to 731.40, 1,009.34 and 399.84 is: 551.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    731.40 : 1,009.34 = 399.84 : x
  2. Step 2: Convert to fraction form
    731.40/1,009.34 = 399.84/x
  3. Step 3: Cross multiply
    731.40x = 1,009.34 × 399.84
  4. Step 4: Simplify right side
    731.40x = 403,574.51
  5. Step 5: Solve for x
    x = 403,574.51/731.40
  6. Step 6: Final answer
    x = 551.78

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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.