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Finding the Fourth Proportional to 1,379.12, 2,065.44 and 647.12

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Solution

The fourth proportional to 1,379.12, 2,065.44 and 647.12 is: 969.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.12 : 2,065.44 = 647.12 : x
  2. Step 2: Convert to fraction form
    1,379.12/2,065.44 = 647.12/x
  3. Step 3: Cross multiply
    1,379.12x = 2,065.44 × 647.12
  4. Step 4: Simplify right side
    1,379.12x = 1,336,587.53
  5. Step 5: Solve for x
    x = 1,336,587.53/1,379.12
  6. Step 6: Final answer
    x = 969.16

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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.