Home / 1,420.72-2,131.08-639.81

Finding the Fourth Proportional to 1,420.72, 2,131.08 and 639.81

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Solution

The fourth proportional to 1,420.72, 2,131.08 and 639.81 is: 959.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.72 : 2,131.08 = 639.81 : x
  2. Step 2: Convert to fraction form
    1,420.72/2,131.08 = 639.81/x
  3. Step 3: Cross multiply
    1,420.72x = 2,131.08 × 639.81
  4. Step 4: Simplify right side
    1,420.72x = 1,363,482.03
  5. Step 5: Solve for x
    x = 1,363,482.03/1,420.72
  6. Step 6: Final answer
    x = 959.71

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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.