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Finding the Fourth Proportional to 715.88, 987.98 and 401.20

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Solution

The fourth proportional to 715.88, 987.98 and 401.20 is: 553.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.88 : 987.98 = 401.20 : x
  2. Step 2: Convert to fraction form
    715.88/987.98 = 401.20/x
  3. Step 3: Cross multiply
    715.88x = 987.98 × 401.20
  4. Step 4: Simplify right side
    715.88x = 396,377.58
  5. Step 5: Solve for x
    x = 396,377.58/715.88
  6. Step 6: Final answer
    x = 553.69

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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.