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Finding the Fourth Proportional to 420.99, 581.21 and 281.57

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Solution

The fourth proportional to 420.99, 581.21 and 281.57 is: 388.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.99 : 581.21 = 281.57 : x
  2. Step 2: Convert to fraction form
    420.99/581.21 = 281.57/x
  3. Step 3: Cross multiply
    420.99x = 581.21 × 281.57
  4. Step 4: Simplify right side
    420.99x = 163,653.46
  5. Step 5: Solve for x
    x = 163,653.46/420.99
  6. Step 6: Final answer
    x = 388.73

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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.