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Finding the Fourth Proportional to 1,209.64, 1,669.08 and 712.20

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Solution

The fourth proportional to 1,209.64, 1,669.08 and 712.20 is: 982.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.64 : 1,669.08 = 712.20 : x
  2. Step 2: Convert to fraction form
    1,209.64/1,669.08 = 712.20/x
  3. Step 3: Cross multiply
    1,209.64x = 1,669.08 × 712.20
  4. Step 4: Simplify right side
    1,209.64x = 1,188,718.78
  5. Step 5: Solve for x
    x = 1,188,718.78/1,209.64
  6. Step 6: Final answer
    x = 982.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.