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Finding the Fourth Proportional to 988.47, 1,479.60 and 728.75

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Solution

The fourth proportional to 988.47, 1,479.60 and 728.75 is: 1,090.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.47 : 1,479.60 = 728.75 : x
  2. Step 2: Convert to fraction form
    988.47/1,479.60 = 728.75/x
  3. Step 3: Cross multiply
    988.47x = 1,479.60 × 728.75
  4. Step 4: Simplify right side
    988.47x = 1,078,262.20
  5. Step 5: Solve for x
    x = 1,078,262.20/988.47
  6. Step 6: Final answer
    x = 1,090.84

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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.