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Finding the Fourth Proportional to 1,238.91, 1,707.71 and 840.45

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Solution

The fourth proportional to 1,238.91, 1,707.71 and 840.45 is: 1,158.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.91 : 1,707.71 = 840.45 : x
  2. Step 2: Convert to fraction form
    1,238.91/1,707.71 = 840.45/x
  3. Step 3: Cross multiply
    1,238.91x = 1,707.71 × 840.45
  4. Step 4: Simplify right side
    1,238.91x = 1,435,240.67
  5. Step 5: Solve for x
    x = 1,435,240.67/1,238.91
  6. Step 6: Final answer
    x = 1,158.47

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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.