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Finding the Fourth Proportional to 988.87, 1,364.36 and 689.78

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Solution

The fourth proportional to 988.87, 1,364.36 and 689.78 is: 951.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.87 : 1,364.36 = 689.78 : x
  2. Step 2: Convert to fraction form
    988.87/1,364.36 = 689.78/x
  3. Step 3: Cross multiply
    988.87x = 1,364.36 × 689.78
  4. Step 4: Simplify right side
    988.87x = 941,108.24
  5. Step 5: Solve for x
    x = 941,108.24/988.87
  6. Step 6: Final answer
    x = 951.70

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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.