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Finding the Fourth Proportional to 1,011.29, 1,395.95 and 638.81

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Solution

The fourth proportional to 1,011.29, 1,395.95 and 638.81 is: 881.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,011.29 : 1,395.95 = 638.81 : x
  2. Step 2: Convert to fraction form
    1,011.29/1,395.95 = 638.81/x
  3. Step 3: Cross multiply
    1,011.29x = 1,395.95 × 638.81
  4. Step 4: Simplify right side
    1,011.29x = 891,736.65
  5. Step 5: Solve for x
    x = 891,736.65/1,011.29
  6. Step 6: Final answer
    x = 881.79

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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.