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Finding the Fourth Proportional to 912.10, 1,256.97 and 690.70

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Solution

The fourth proportional to 912.10, 1,256.97 and 690.70 is: 951.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.10 : 1,256.97 = 690.70 : x
  2. Step 2: Convert to fraction form
    912.10/1,256.97 = 690.70/x
  3. Step 3: Cross multiply
    912.10x = 1,256.97 × 690.70
  4. Step 4: Simplify right side
    912.10x = 868,189.18
  5. Step 5: Solve for x
    x = 868,189.18/912.10
  6. Step 6: Final answer
    x = 951.86

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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.