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Finding the Fourth Proportional to 1,312.21, 1,969.53 and 663.40

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Solution

The fourth proportional to 1,312.21, 1,969.53 and 663.40 is: 995.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,312.21 : 1,969.53 = 663.40 : x
  2. Step 2: Convert to fraction form
    1,312.21/1,969.53 = 663.40/x
  3. Step 3: Cross multiply
    1,312.21x = 1,969.53 × 663.40
  4. Step 4: Simplify right side
    1,312.21x = 1,306,581.28
  5. Step 5: Solve for x
    x = 1,306,581.28/1,312.21
  6. Step 6: Final answer
    x = 995.71

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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.