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Finding the Fourth Proportional to 620.80, 931.40 and 415.60

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Solution

The fourth proportional to 620.80, 931.40 and 415.60 is: 623.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.80 : 931.40 = 415.60 : x
  2. Step 2: Convert to fraction form
    620.80/931.40 = 415.60/x
  3. Step 3: Cross multiply
    620.80x = 931.40 × 415.60
  4. Step 4: Simplify right side
    620.80x = 387,089.84
  5. Step 5: Solve for x
    x = 387,089.84/620.80
  6. Step 6: Final answer
    x = 623.53

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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.