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Finding the Fourth Proportional to 1,419.86, 2,130.32 and 639.63

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Solution

The fourth proportional to 1,419.86, 2,130.32 and 639.63 is: 959.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,419.86 : 2,130.32 = 639.63 : x
  2. Step 2: Convert to fraction form
    1,419.86/2,130.32 = 639.63/x
  3. Step 3: Cross multiply
    1,419.86x = 2,130.32 × 639.63
  4. Step 4: Simplify right side
    1,419.86x = 1,362,618.18
  5. Step 5: Solve for x
    x = 1,362,618.18/1,419.86
  6. Step 6: Final answer
    x = 959.68

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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.