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Finding the Fourth Proportional to 939.80, 1,409.88 and 477.20

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Solution

The fourth proportional to 939.80, 1,409.88 and 477.20 is: 715.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.80 : 1,409.88 = 477.20 : x
  2. Step 2: Convert to fraction form
    939.80/1,409.88 = 477.20/x
  3. Step 3: Cross multiply
    939.80x = 1,409.88 × 477.20
  4. Step 4: Simplify right side
    939.80x = 672,794.74
  5. Step 5: Solve for x
    x = 672,794.74/939.80
  6. Step 6: Final answer
    x = 715.89

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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.