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Finding the Fourth Proportional to 306.21, 421.65 and 257.01

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Solution

The fourth proportional to 306.21, 421.65 and 257.01 is: 353.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.21 : 421.65 = 257.01 : x
  2. Step 2: Convert to fraction form
    306.21/421.65 = 257.01/x
  3. Step 3: Cross multiply
    306.21x = 421.65 × 257.01
  4. Step 4: Simplify right side
    306.21x = 108,368.27
  5. Step 5: Solve for x
    x = 108,368.27/306.21
  6. Step 6: Final answer
    x = 353.90

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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.