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Finding the Fourth Proportional to 1,318.68, 1,819.71 and 721.15

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Solution

The fourth proportional to 1,318.68, 1,819.71 and 721.15 is: 995.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.68 : 1,819.71 = 721.15 : x
  2. Step 2: Convert to fraction form
    1,318.68/1,819.71 = 721.15/x
  3. Step 3: Cross multiply
    1,318.68x = 1,819.71 × 721.15
  4. Step 4: Simplify right side
    1,318.68x = 1,312,292.26
  5. Step 5: Solve for x
    x = 1,312,292.26/1,318.68
  6. Step 6: Final answer
    x = 995.16

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1.5x scale

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.