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Finding the Fourth Proportional to 1,290.34, 1,781.14 and 766.38

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Solution

The fourth proportional to 1,290.34, 1,781.14 and 766.38 is: 1,057.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.34 : 1,781.14 = 766.38 : x
  2. Step 2: Convert to fraction form
    1,290.34/1,781.14 = 766.38/x
  3. Step 3: Cross multiply
    1,290.34x = 1,781.14 × 766.38
  4. Step 4: Simplify right side
    1,290.34x = 1,365,030.07
  5. Step 5: Solve for x
    x = 1,365,030.07/1,290.34
  6. Step 6: Final answer
    x = 1,057.88

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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.