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Finding the Fourth Proportional to 978.76, 1,351.22 and 711.20

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Solution

The fourth proportional to 978.76, 1,351.22 and 711.20 is: 981.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.76 : 1,351.22 = 711.20 : x
  2. Step 2: Convert to fraction form
    978.76/1,351.22 = 711.20/x
  3. Step 3: Cross multiply
    978.76x = 1,351.22 × 711.20
  4. Step 4: Simplify right side
    978.76x = 960,987.66
  5. Step 5: Solve for x
    x = 960,987.66/978.76
  6. Step 6: Final answer
    x = 981.84

Related Problems

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Half scale
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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.