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Finding the Fourth Proportional to 1,079.80, 1,618.90 and 430.20

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Solution

The fourth proportional to 1,079.80, 1,618.90 and 430.20 is: 644.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.80 : 1,618.90 = 430.20 : x
  2. Step 2: Convert to fraction form
    1,079.80/1,618.90 = 430.20/x
  3. Step 3: Cross multiply
    1,079.80x = 1,618.90 × 430.20
  4. Step 4: Simplify right side
    1,079.80x = 696,450.78
  5. Step 5: Solve for x
    x = 696,450.78/1,079.80
  6. Step 6: Final answer
    x = 644.98

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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.