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Finding the Fourth Proportional to 1,720.40, 2,580.60 and 421.86

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Solution

The fourth proportional to 1,720.40, 2,580.60 and 421.86 is: 632.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,720.40 : 2,580.60 = 421.86 : x
  2. Step 2: Convert to fraction form
    1,720.40/2,580.60 = 421.86/x
  3. Step 3: Cross multiply
    1,720.40x = 2,580.60 × 421.86
  4. Step 4: Simplify right side
    1,720.40x = 1,088,651.92
  5. Step 5: Solve for x
    x = 1,088,651.92/1,720.40
  6. Step 6: Final answer
    x = 632.79

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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.