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Finding the Fourth Proportional to 715.30, 987.18 and 420.56

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Solution

The fourth proportional to 715.30, 987.18 and 420.56 is: 580.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.30 : 987.18 = 420.56 : x
  2. Step 2: Convert to fraction form
    715.30/987.18 = 420.56/x
  3. Step 3: Cross multiply
    715.30x = 987.18 × 420.56
  4. Step 4: Simplify right side
    715.30x = 415,168.42
  5. Step 5: Solve for x
    x = 415,168.42/715.30
  6. Step 6: Final answer
    x = 580.41

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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.