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Finding the Fourth Proportional to 1,298.40, 1,791.75 and 708.90

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Solution

The fourth proportional to 1,298.40, 1,791.75 and 708.90 is: 978.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,298.40 : 1,791.75 = 708.90 : x
  2. Step 2: Convert to fraction form
    1,298.40/1,791.75 = 708.90/x
  3. Step 3: Cross multiply
    1,298.40x = 1,791.75 × 708.90
  4. Step 4: Simplify right side
    1,298.40x = 1,270,171.58
  5. Step 5: Solve for x
    x = 1,270,171.58/1,298.40
  6. Step 6: Final answer
    x = 978.26

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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.