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Finding the Fourth Proportional to 1,216.75, 1,679.12 and 664.75

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Solution

The fourth proportional to 1,216.75, 1,679.12 and 664.75 is: 917.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,216.75 : 1,679.12 = 664.75 : x
  2. Step 2: Convert to fraction form
    1,216.75/1,679.12 = 664.75/x
  3. Step 3: Cross multiply
    1,216.75x = 1,679.12 × 664.75
  4. Step 4: Simplify right side
    1,216.75x = 1,116,195.02
  5. Step 5: Solve for x
    x = 1,116,195.02/1,216.75
  6. Step 6: Final answer
    x = 917.36

Related Problems

Find fourth proportional to 608.38, 839.56 and 332.38
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.