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Finding the Fourth Proportional to 1,209.56, 1,669.10 and 678.35

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Solution

The fourth proportional to 1,209.56, 1,669.10 and 678.35 is: 936.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.56 : 1,669.10 = 678.35 : x
  2. Step 2: Convert to fraction form
    1,209.56/1,669.10 = 678.35/x
  3. Step 3: Cross multiply
    1,209.56x = 1,669.10 × 678.35
  4. Step 4: Simplify right side
    1,209.56x = 1,132,227.34
  5. Step 5: Solve for x
    x = 1,132,227.34/1,209.56
  6. Step 6: Final answer
    x = 936.07

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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.