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Finding the Fourth Proportional to 421.76, 632.70 and 257.33

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Solution

The fourth proportional to 421.76, 632.70 and 257.33 is: 386.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.76 : 632.70 = 257.33 : x
  2. Step 2: Convert to fraction form
    421.76/632.70 = 257.33/x
  3. Step 3: Cross multiply
    421.76x = 632.70 × 257.33
  4. Step 4: Simplify right side
    421.76x = 162,809.53
  5. Step 5: Solve for x
    x = 162,809.53/421.76
  6. Step 6: Final answer
    x = 386.03

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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.