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Finding the Fourth Proportional to 877.72, 1,211.60 and 638.80

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Solution

The fourth proportional to 877.72, 1,211.60 and 638.80 is: 881.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.72 : 1,211.60 = 638.80 : x
  2. Step 2: Convert to fraction form
    877.72/1,211.60 = 638.80/x
  3. Step 3: Cross multiply
    877.72x = 1,211.60 × 638.80
  4. Step 4: Simplify right side
    877.72x = 773,970.08
  5. Step 5: Solve for x
    x = 773,970.08/877.72
  6. Step 6: Final answer
    x = 881.80

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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.