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Finding the Fourth Proportional to 1,128.80, 1,693.66 and 480

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Solution

The fourth proportional to 1,128.80, 1,693.66 and 480 is: 720.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.80 : 1,693.66 = 480 : x
  2. Step 2: Convert to fraction form
    1,128.80/1,693.66 = 480/x
  3. Step 3: Cross multiply
    1,128.80x = 1,693.66 × 480
  4. Step 4: Simplify right side
    1,128.80x = 812,956.80
  5. Step 5: Solve for x
    x = 812,956.80/1,128.80
  6. Step 6: Final answer
    x = 720.20

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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.