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Finding the Fourth Proportional to 1,209.80, 1,815.12 and 479.84

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Solution

The fourth proportional to 1,209.80, 1,815.12 and 479.84 is: 719.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.80 : 1,815.12 = 479.84 : x
  2. Step 2: Convert to fraction form
    1,209.80/1,815.12 = 479.84/x
  3. Step 3: Cross multiply
    1,209.80x = 1,815.12 × 479.84
  4. Step 4: Simplify right side
    1,209.80x = 870,967.18
  5. Step 5: Solve for x
    x = 870,967.18/1,209.80
  6. Step 6: Final answer
    x = 719.93

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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.