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Finding the Fourth Proportional to 1,220.99, 1,684.80 and 689.79

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Solution

The fourth proportional to 1,220.99, 1,684.80 and 689.79 is: 951.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.99 : 1,684.80 = 689.79 : x
  2. Step 2: Convert to fraction form
    1,220.99/1,684.80 = 689.79/x
  3. Step 3: Cross multiply
    1,220.99x = 1,684.80 × 689.79
  4. Step 4: Simplify right side
    1,220.99x = 1,162,149.77
  5. Step 5: Solve for x
    x = 1,162,149.77/1,220.99
  6. Step 6: Final answer
    x = 951.81

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.