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Finding the Fourth Proportional to 786.95, 1,178.10 and 689.64

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Solution

The fourth proportional to 786.95, 1,178.10 and 689.64 is: 1,032.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.95 : 1,178.10 = 689.64 : x
  2. Step 2: Convert to fraction form
    786.95/1,178.10 = 689.64/x
  3. Step 3: Cross multiply
    786.95x = 1,178.10 × 689.64
  4. Step 4: Simplify right side
    786.95x = 812,464.88
  5. Step 5: Solve for x
    x = 812,464.88/786.95
  6. Step 6: Final answer
    x = 1,032.43

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.