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Finding the Fourth Proportional to 1,080.60, 1,621.30 and 431.80

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Solution

The fourth proportional to 1,080.60, 1,621.30 and 431.80 is: 647.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,080.60 : 1,621.30 = 431.80 : x
  2. Step 2: Convert to fraction form
    1,080.60/1,621.30 = 431.80/x
  3. Step 3: Cross multiply
    1,080.60x = 1,621.30 × 431.80
  4. Step 4: Simplify right side
    1,080.60x = 700,077.34
  5. Step 5: Solve for x
    x = 700,077.34/1,080.60
  6. Step 6: Final answer
    x = 647.86

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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.