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Finding the Fourth Proportional to 908.40, 1,362.57 and 420.78

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Solution

The fourth proportional to 908.40, 1,362.57 and 420.78 is: 631.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.40 : 1,362.57 = 420.78 : x
  2. Step 2: Convert to fraction form
    908.40/1,362.57 = 420.78/x
  3. Step 3: Cross multiply
    908.40x = 1,362.57 × 420.78
  4. Step 4: Simplify right side
    908.40x = 573,342.20
  5. Step 5: Solve for x
    x = 573,342.20/908.40
  6. Step 6: Final answer
    x = 631.16

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.