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Finding the Fourth Proportional to 787.79, 1,087.18 and 438.50

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Solution

The fourth proportional to 787.79, 1,087.18 and 438.50 is: 605.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.79 : 1,087.18 = 438.50 : x
  2. Step 2: Convert to fraction form
    787.79/1,087.18 = 438.50/x
  3. Step 3: Cross multiply
    787.79x = 1,087.18 × 438.50
  4. Step 4: Simplify right side
    787.79x = 476,730.05
  5. Step 5: Solve for x
    x = 476,730.05/787.79
  6. Step 6: Final answer
    x = 605.15

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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.