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Finding the Fourth Proportional to 1,221.47, 1,685.56 and 690.46

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Solution

The fourth proportional to 1,221.47, 1,685.56 and 690.46 is: 952.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.47 : 1,685.56 = 690.46 : x
  2. Step 2: Convert to fraction form
    1,221.47/1,685.56 = 690.46/x
  3. Step 3: Cross multiply
    1,221.47x = 1,685.56 × 690.46
  4. Step 4: Simplify right side
    1,221.47x = 1,163,811.76
  5. Step 5: Solve for x
    x = 1,163,811.76/1,221.47
  6. Step 6: Final answer
    x = 952.80

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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.