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Finding the Fourth Proportional to 987.22, 1,362.12 and 668.78

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Solution

The fourth proportional to 987.22, 1,362.12 and 668.78 is: 922.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.22 : 1,362.12 = 668.78 : x
  2. Step 2: Convert to fraction form
    987.22/1,362.12 = 668.78/x
  3. Step 3: Cross multiply
    987.22x = 1,362.12 × 668.78
  4. Step 4: Simplify right side
    987.22x = 910,956.91
  5. Step 5: Solve for x
    x = 910,956.91/987.22
  6. Step 6: Final answer
    x = 922.75

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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.