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Finding the Fourth Proportional to 838.79, 1,258.31 and 318.99

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Solution

The fourth proportional to 838.79, 1,258.31 and 318.99 is: 478.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.79 : 1,258.31 = 318.99 : x
  2. Step 2: Convert to fraction form
    838.79/1,258.31 = 318.99/x
  3. Step 3: Cross multiply
    838.79x = 1,258.31 × 318.99
  4. Step 4: Simplify right side
    838.79x = 401,386.71
  5. Step 5: Solve for x
    x = 401,386.71/838.79
  6. Step 6: Final answer
    x = 478.53

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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.