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Finding the Fourth Proportional to 1,386.72, 2,079.64 and 412.88

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Solution

The fourth proportional to 1,386.72, 2,079.64 and 412.88 is: 619.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.72 : 2,079.64 = 412.88 : x
  2. Step 2: Convert to fraction form
    1,386.72/2,079.64 = 412.88/x
  3. Step 3: Cross multiply
    1,386.72x = 2,079.64 × 412.88
  4. Step 4: Simplify right side
    1,386.72x = 858,641.76
  5. Step 5: Solve for x
    x = 858,641.76/1,386.72
  6. Step 6: Final answer
    x = 619.19

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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.