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Finding the Fourth Proportional to 642.25, 886.15 and 380.12

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Solution

The fourth proportional to 642.25, 886.15 and 380.12 is: 524.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.25 : 886.15 = 380.12 : x
  2. Step 2: Convert to fraction form
    642.25/886.15 = 380.12/x
  3. Step 3: Cross multiply
    642.25x = 886.15 × 380.12
  4. Step 4: Simplify right side
    642.25x = 336,843.34
  5. Step 5: Solve for x
    x = 336,843.34/642.25
  6. Step 6: Final answer
    x = 524.47

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Double scale
Find fourth proportional to 643.25, 887.53 and 381.12
Similar ratio
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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.