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Finding the Fourth Proportional to 421.70, 581.42 and 274.28

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Solution

The fourth proportional to 421.70, 581.42 and 274.28 is: 378.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.70 : 581.42 = 274.28 : x
  2. Step 2: Convert to fraction form
    421.70/581.42 = 274.28/x
  3. Step 3: Cross multiply
    421.70x = 581.42 × 274.28
  4. Step 4: Simplify right side
    421.70x = 159,471.88
  5. Step 5: Solve for x
    x = 159,471.88/421.70
  6. Step 6: Final answer
    x = 378.16

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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.