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Finding the Fourth Proportional to 787.96, 1,089.30 and 715.96

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Solution

The fourth proportional to 787.96, 1,089.30 and 715.96 is: 989.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.96 : 1,089.30 = 715.96 : x
  2. Step 2: Convert to fraction form
    787.96/1,089.30 = 715.96/x
  3. Step 3: Cross multiply
    787.96x = 1,089.30 × 715.96
  4. Step 4: Simplify right side
    787.96x = 779,895.23
  5. Step 5: Solve for x
    x = 779,895.23/787.96
  6. Step 6: Final answer
    x = 989.76

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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.