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Finding the Fourth Proportional to 685.55, 1,022.38 and 661.64

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Solution

The fourth proportional to 685.55, 1,022.38 and 661.64 is: 986.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.55 : 1,022.38 = 661.64 : x
  2. Step 2: Convert to fraction form
    685.55/1,022.38 = 661.64/x
  3. Step 3: Cross multiply
    685.55x = 1,022.38 × 661.64
  4. Step 4: Simplify right side
    685.55x = 676,440.74
  5. Step 5: Solve for x
    x = 676,440.74/685.55
  6. Step 6: Final answer
    x = 986.71

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.