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Finding the Fourth Proportional to 786.38, 1,085.31 and 491.49

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Solution

The fourth proportional to 786.38, 1,085.31 and 491.49 is: 678.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.38 : 1,085.31 = 491.49 : x
  2. Step 2: Convert to fraction form
    786.38/1,085.31 = 491.49/x
  3. Step 3: Cross multiply
    786.38x = 1,085.31 × 491.49
  4. Step 4: Simplify right side
    786.38x = 533,419.01
  5. Step 5: Solve for x
    x = 533,419.01/786.38
  6. Step 6: Final answer
    x = 678.33

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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.