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Finding the Fourth Proportional to 421.12, 630.40 and 305.12

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Solution

The fourth proportional to 421.12, 630.40 and 305.12 is: 456.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.12 : 630.40 = 305.12 : x
  2. Step 2: Convert to fraction form
    421.12/630.40 = 305.12/x
  3. Step 3: Cross multiply
    421.12x = 630.40 × 305.12
  4. Step 4: Simplify right side
    421.12x = 192,347.65
  5. Step 5: Solve for x
    x = 192,347.65/421.12
  6. Step 6: Final answer
    x = 456.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.