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Finding the Fourth Proportional to 715.27, 987.29 and 420.61

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Solution

The fourth proportional to 715.27, 987.29 and 420.61 is: 580.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.27 : 987.29 = 420.61 : x
  2. Step 2: Convert to fraction form
    715.27/987.29 = 420.61/x
  3. Step 3: Cross multiply
    715.27x = 987.29 × 420.61
  4. Step 4: Simplify right side
    715.27x = 415,264.05
  5. Step 5: Solve for x
    x = 415,264.05/715.27
  6. Step 6: Final answer
    x = 580.57

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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.