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Finding the Fourth Proportional to 718.15, 990.78 and 438.19

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Solution

The fourth proportional to 718.15, 990.78 and 438.19 is: 604.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.15 : 990.78 = 438.19 : x
  2. Step 2: Convert to fraction form
    718.15/990.78 = 438.19/x
  3. Step 3: Cross multiply
    718.15x = 990.78 × 438.19
  4. Step 4: Simplify right side
    718.15x = 434,149.89
  5. Step 5: Solve for x
    x = 434,149.89/718.15
  6. Step 6: Final answer
    x = 604.54

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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.