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Finding the Fourth Proportional to 720.40, 993.62 and 621

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Solution

The fourth proportional to 720.40, 993.62 and 621 is: 856.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.40 : 993.62 = 621 : x
  2. Step 2: Convert to fraction form
    720.40/993.62 = 621/x
  3. Step 3: Cross multiply
    720.40x = 993.62 × 621
  4. Step 4: Simplify right side
    720.40x = 617,038.02
  5. Step 5: Solve for x
    x = 617,038.02/720.40
  6. Step 6: Final answer
    x = 856.52

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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.