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Finding the Fourth Proportional to 975.19, 1,345.35 and 643.54

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Solution

The fourth proportional to 975.19, 1,345.35 and 643.54 is: 887.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    975.19 : 1,345.35 = 643.54 : x
  2. Step 2: Convert to fraction form
    975.19/1,345.35 = 643.54/x
  3. Step 3: Cross multiply
    975.19x = 1,345.35 × 643.54
  4. Step 4: Simplify right side
    975.19x = 865,786.54
  5. Step 5: Solve for x
    x = 865,786.54/975.19
  6. Step 6: Final answer
    x = 887.81

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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.