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Finding the Fourth Proportional to 1,381.95, 2,070.15 and 686.51

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Solution

The fourth proportional to 1,381.95, 2,070.15 and 686.51 is: 1,028.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.95 : 2,070.15 = 686.51 : x
  2. Step 2: Convert to fraction form
    1,381.95/2,070.15 = 686.51/x
  3. Step 3: Cross multiply
    1,381.95x = 2,070.15 × 686.51
  4. Step 4: Simplify right side
    1,381.95x = 1,421,181.28
  5. Step 5: Solve for x
    x = 1,421,181.28/1,381.95
  6. Step 6: Final answer
    x = 1,028.39

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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.