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Finding the Fourth Proportional to 1,289.12, 1,778.64 and 823.64

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Solution

The fourth proportional to 1,289.12, 1,778.64 and 823.64 is: 1,136.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.12 : 1,778.64 = 823.64 : x
  2. Step 2: Convert to fraction form
    1,289.12/1,778.64 = 823.64/x
  3. Step 3: Cross multiply
    1,289.12x = 1,778.64 × 823.64
  4. Step 4: Simplify right side
    1,289.12x = 1,464,959.05
  5. Step 5: Solve for x
    x = 1,464,959.05/1,289.12
  6. Step 6: Final answer
    x = 1,136.40

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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.