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Finding the Fourth Proportional to 867.40, 1,298.36 and 685.15

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Solution

The fourth proportional to 867.40, 1,298.36 and 685.15 is: 1,025.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    867.40 : 1,298.36 = 685.15 : x
  2. Step 2: Convert to fraction form
    867.40/1,298.36 = 685.15/x
  3. Step 3: Cross multiply
    867.40x = 1,298.36 × 685.15
  4. Step 4: Simplify right side
    867.40x = 889,569.82
  5. Step 5: Solve for x
    x = 889,569.82/867.40
  6. Step 6: Final answer
    x = 1,025.56

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.