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Finding the Fourth Proportional to 939.63, 1,407.18 and 613.20

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Solution

The fourth proportional to 939.63, 1,407.18 and 613.20 is: 918.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.63 : 1,407.18 = 613.20 : x
  2. Step 2: Convert to fraction form
    939.63/1,407.18 = 613.20/x
  3. Step 3: Cross multiply
    939.63x = 1,407.18 × 613.20
  4. Step 4: Simplify right side
    939.63x = 862,882.78
  5. Step 5: Solve for x
    x = 862,882.78/939.63
  6. Step 6: Final answer
    x = 918.32

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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.