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Finding the Fourth Proportional to 715.57, 987.47 and 400.86

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Solution

The fourth proportional to 715.57, 987.47 and 400.86 is: 553.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.57 : 987.47 = 400.86 : x
  2. Step 2: Convert to fraction form
    715.57/987.47 = 400.86/x
  3. Step 3: Cross multiply
    715.57x = 987.47 × 400.86
  4. Step 4: Simplify right side
    715.57x = 395,837.22
  5. Step 5: Solve for x
    x = 395,837.22/715.57
  6. Step 6: Final answer
    x = 553.18

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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.