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Finding the Fourth Proportional to 787.98, 1,086.30 and 631.14

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Solution

The fourth proportional to 787.98, 1,086.30 and 631.14 is: 870.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.98 : 1,086.30 = 631.14 : x
  2. Step 2: Convert to fraction form
    787.98/1,086.30 = 631.14/x
  3. Step 3: Cross multiply
    787.98x = 1,086.30 × 631.14
  4. Step 4: Simplify right side
    787.98x = 685,607.38
  5. Step 5: Solve for x
    x = 685,607.38/787.98
  6. Step 6: Final answer
    x = 870.08

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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.