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Finding the Fourth Proportional to 787.17, 1,087.40 and 630.84

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Solution

The fourth proportional to 787.17, 1,087.40 and 630.84 is: 871.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.17 : 1,087.40 = 630.84 : x
  2. Step 2: Convert to fraction form
    787.17/1,087.40 = 630.84/x
  3. Step 3: Cross multiply
    787.17x = 1,087.40 × 630.84
  4. Step 4: Simplify right side
    787.17x = 685,975.42
  5. Step 5: Solve for x
    x = 685,975.42/787.17
  6. Step 6: Final answer
    x = 871.45

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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.