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Finding the Fourth Proportional to 689.12, 949.02 and 645.20

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Solution

The fourth proportional to 689.12, 949.02 and 645.20 is: 888.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.12 : 949.02 = 645.20 : x
  2. Step 2: Convert to fraction form
    689.12/949.02 = 645.20/x
  3. Step 3: Cross multiply
    689.12x = 949.02 × 645.20
  4. Step 4: Simplify right side
    689.12x = 612,307.70
  5. Step 5: Solve for x
    x = 612,307.70/689.12
  6. Step 6: Final answer
    x = 888.54

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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.