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Finding the Fourth Proportional to 811.24, 1,117.56 and 645.40

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Solution

The fourth proportional to 811.24, 1,117.56 and 645.40 is: 889.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.24 : 1,117.56 = 645.40 : x
  2. Step 2: Convert to fraction form
    811.24/1,117.56 = 645.40/x
  3. Step 3: Cross multiply
    811.24x = 1,117.56 × 645.40
  4. Step 4: Simplify right side
    811.24x = 721,273.22
  5. Step 5: Solve for x
    x = 721,273.22/811.24
  6. Step 6: Final answer
    x = 889.10

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Double scale
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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.