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Finding the Fourth Proportional to 988.35, 1,479.41 and 678.39

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Solution

The fourth proportional to 988.35, 1,479.41 and 678.39 is: 1,015.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.35 : 1,479.41 = 678.39 : x
  2. Step 2: Convert to fraction form
    988.35/1,479.41 = 678.39/x
  3. Step 3: Cross multiply
    988.35x = 1,479.41 × 678.39
  4. Step 4: Simplify right side
    988.35x = 1,003,613.10
  5. Step 5: Solve for x
    x = 1,003,613.10/988.35
  6. Step 6: Final answer
    x = 1,015.45

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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.