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Finding the Fourth Proportional to 715.72, 987.70 and 400.99

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Solution

The fourth proportional to 715.72, 987.70 and 400.99 is: 553.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.72 : 987.70 = 400.99 : x
  2. Step 2: Convert to fraction form
    715.72/987.70 = 400.99/x
  3. Step 3: Cross multiply
    715.72x = 987.70 × 400.99
  4. Step 4: Simplify right side
    715.72x = 396,052.88
  5. Step 5: Solve for x
    x = 396,052.88/715.72
  6. Step 6: Final answer
    x = 553.37

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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.