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Finding the Fourth Proportional to 421.42, 581.52 and 390.46

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Solution

The fourth proportional to 421.42, 581.52 and 390.46 is: 538.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.42 : 581.52 = 390.46 : x
  2. Step 2: Convert to fraction form
    421.42/581.52 = 390.46/x
  3. Step 3: Cross multiply
    421.42x = 581.52 × 390.46
  4. Step 4: Simplify right side
    421.42x = 227,060.30
  5. Step 5: Solve for x
    x = 227,060.30/421.42
  6. Step 6: Final answer
    x = 538.80

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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.