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Finding the Fourth Proportional to 721.08, 991.49 and 615.74

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Solution

The fourth proportional to 721.08, 991.49 and 615.74 is: 846.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.08 : 991.49 = 615.74 : x
  2. Step 2: Convert to fraction form
    721.08/991.49 = 615.74/x
  3. Step 3: Cross multiply
    721.08x = 991.49 × 615.74
  4. Step 4: Simplify right side
    721.08x = 610,492.02
  5. Step 5: Solve for x
    x = 610,492.02/721.08
  6. Step 6: Final answer
    x = 846.64

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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.