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Finding the Fourth Proportional to 715.20, 987.04 and 420.32

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Solution

The fourth proportional to 715.20, 987.04 and 420.32 is: 580.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.20 : 987.04 = 420.32 : x
  2. Step 2: Convert to fraction form
    715.20/987.04 = 420.32/x
  3. Step 3: Cross multiply
    715.20x = 987.04 × 420.32
  4. Step 4: Simplify right side
    715.20x = 414,872.65
  5. Step 5: Solve for x
    x = 414,872.65/715.20
  6. Step 6: Final answer
    x = 580.08

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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.