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Finding the Fourth Proportional to 1,387.90, 2,082.84 and 657.64

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Solution

The fourth proportional to 1,387.90, 2,082.84 and 657.64 is: 986.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.90 : 2,082.84 = 657.64 : x
  2. Step 2: Convert to fraction form
    1,387.90/2,082.84 = 657.64/x
  3. Step 3: Cross multiply
    1,387.90x = 2,082.84 × 657.64
  4. Step 4: Simplify right side
    1,387.90x = 1,369,758.90
  5. Step 5: Solve for x
    x = 1,369,758.90/1,387.90
  6. Step 6: Final answer
    x = 986.93

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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.