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Finding the Fourth Proportional to 623.50, 860.43 and 390.76

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Solution

The fourth proportional to 623.50, 860.43 and 390.76 is: 539.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    623.50 : 860.43 = 390.76 : x
  2. Step 2: Convert to fraction form
    623.50/860.43 = 390.76/x
  3. Step 3: Cross multiply
    623.50x = 860.43 × 390.76
  4. Step 4: Simplify right side
    623.50x = 336,221.63
  5. Step 5: Solve for x
    x = 336,221.63/623.50
  6. Step 6: Final answer
    x = 539.25

Related Problems

Find fourth proportional to 311.75, 430.22 and 195.38
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Double scale
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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.