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Finding the Fourth Proportional to 489.76, 675.84 and 315.20

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Solution

The fourth proportional to 489.76, 675.84 and 315.20 is: 434.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.76 : 675.84 = 315.20 : x
  2. Step 2: Convert to fraction form
    489.76/675.84 = 315.20/x
  3. Step 3: Cross multiply
    489.76x = 675.84 × 315.20
  4. Step 4: Simplify right side
    489.76x = 213,024.77
  5. Step 5: Solve for x
    x = 213,024.77/489.76
  6. Step 6: Final answer
    x = 434.96

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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.