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Finding the Fourth Proportional to 220, 303.60 and 128

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Solution

The fourth proportional to 220, 303.60 and 128 is: 176.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    220 : 303.60 = 128 : x
  2. Step 2: Convert to fraction form
    220/303.60 = 128/x
  3. Step 3: Cross multiply
    220x = 303.60 × 128
  4. Step 4: Simplify right side
    220x = 38,860.80
  5. Step 5: Solve for x
    x = 38,860.80/220
  6. Step 6: Final answer
    x = 176.64

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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.