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Finding the Fourth Proportional to 715.28, 987.32 and 420.44

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Solution

The fourth proportional to 715.28, 987.32 and 420.44 is: 580.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.28 : 987.32 = 420.44 : x
  2. Step 2: Convert to fraction form
    715.28/987.32 = 420.44/x
  3. Step 3: Cross multiply
    715.28x = 987.32 × 420.44
  4. Step 4: Simplify right side
    715.28x = 415,108.82
  5. Step 5: Solve for x
    x = 415,108.82/715.28
  6. Step 6: Final answer
    x = 580.34

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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.