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Finding the Fourth Proportional to 1,419.74, 2,128.87 and 639.07

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Solution

The fourth proportional to 1,419.74, 2,128.87 and 639.07 is: 958.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,419.74 : 2,128.87 = 639.07 : x
  2. Step 2: Convert to fraction form
    1,419.74/2,128.87 = 639.07/x
  3. Step 3: Cross multiply
    1,419.74x = 2,128.87 × 639.07
  4. Step 4: Simplify right side
    1,419.74x = 1,360,483.11
  5. Step 5: Solve for x
    x = 1,360,483.11/1,419.74
  6. Step 6: Final answer
    x = 958.26

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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.