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Finding the Fourth Proportional to 935.40, 1,290.80 and 521.40

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Solution

The fourth proportional to 935.40, 1,290.80 and 521.40 is: 719.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    935.40 : 1,290.80 = 521.40 : x
  2. Step 2: Convert to fraction form
    935.40/1,290.80 = 521.40/x
  3. Step 3: Cross multiply
    935.40x = 1,290.80 × 521.40
  4. Step 4: Simplify right side
    935.40x = 673,023.12
  5. Step 5: Solve for x
    x = 673,023.12/935.40
  6. Step 6: Final answer
    x = 719.50

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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.