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Finding the Fourth Proportional to 715.24, 986.87 and 420.40

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Solution

The fourth proportional to 715.24, 986.87 and 420.40 is: 580.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.24 : 986.87 = 420.40 : x
  2. Step 2: Convert to fraction form
    715.24/986.87 = 420.40/x
  3. Step 3: Cross multiply
    715.24x = 986.87 × 420.40
  4. Step 4: Simplify right side
    715.24x = 414,876.88
  5. Step 5: Solve for x
    x = 414,876.88/715.24
  6. Step 6: Final answer
    x = 580.06

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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.