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Finding the Fourth Proportional to 1,021.30, 1,407.41 and 689.15

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Solution

The fourth proportional to 1,021.30, 1,407.41 and 689.15 is: 949.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,021.30 : 1,407.41 = 689.15 : x
  2. Step 2: Convert to fraction form
    1,021.30/1,407.41 = 689.15/x
  3. Step 3: Cross multiply
    1,021.30x = 1,407.41 × 689.15
  4. Step 4: Simplify right side
    1,021.30x = 969,916.60
  5. Step 5: Solve for x
    x = 969,916.60/1,021.30
  6. Step 6: Final answer
    x = 949.69

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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.