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Finding the Fourth Proportional to 828.64, 1,242.90 and 315.28

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Solution

The fourth proportional to 828.64, 1,242.90 and 315.28 is: 472.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.64 : 1,242.90 = 315.28 : x
  2. Step 2: Convert to fraction form
    828.64/1,242.90 = 315.28/x
  3. Step 3: Cross multiply
    828.64x = 1,242.90 × 315.28
  4. Step 4: Simplify right side
    828.64x = 391,861.51
  5. Step 5: Solve for x
    x = 391,861.51/828.64
  6. Step 6: Final answer
    x = 472.90

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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.