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Finding the Fourth Proportional to 1,210, 1,669.80 and 686.14

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Solution

The fourth proportional to 1,210, 1,669.80 and 686.14 is: 946.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210 : 1,669.80 = 686.14 : x
  2. Step 2: Convert to fraction form
    1,210/1,669.80 = 686.14/x
  3. Step 3: Cross multiply
    1,210x = 1,669.80 × 686.14
  4. Step 4: Simplify right side
    1,210x = 1,145,716.57
  5. Step 5: Solve for x
    x = 1,145,716.57/1,210
  6. Step 6: Final answer
    x = 946.87

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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.