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Finding the Fourth Proportional to 1,217.64, 1,680.38 and 720.71

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Solution

The fourth proportional to 1,217.64, 1,680.38 and 720.71 is: 994.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,217.64 : 1,680.38 = 720.71 : x
  2. Step 2: Convert to fraction form
    1,217.64/1,680.38 = 720.71/x
  3. Step 3: Cross multiply
    1,217.64x = 1,680.38 × 720.71
  4. Step 4: Simplify right side
    1,217.64x = 1,211,066.67
  5. Step 5: Solve for x
    x = 1,211,066.67/1,217.64
  6. Step 6: Final answer
    x = 994.60

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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.