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Finding the Fourth Proportional to 420.80, 580.75 and 255.15

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Solution

The fourth proportional to 420.80, 580.75 and 255.15 is: 352.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.80 : 580.75 = 255.15 : x
  2. Step 2: Convert to fraction form
    420.80/580.75 = 255.15/x
  3. Step 3: Cross multiply
    420.80x = 580.75 × 255.15
  4. Step 4: Simplify right side
    420.80x = 148,178.36
  5. Step 5: Solve for x
    x = 148,178.36/420.80
  6. Step 6: Final answer
    x = 352.13

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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.