Home / 668.78-1,003.21-206.61

Finding the Fourth Proportional to 668.78, 1,003.21 and 206.61

Calculator

Solution

The fourth proportional to 668.78, 1,003.21 and 206.61 is: 309.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.78 : 1,003.21 = 206.61 : x
  2. Step 2: Convert to fraction form
    668.78/1,003.21 = 206.61/x
  3. Step 3: Cross multiply
    668.78x = 1,003.21 × 206.61
  4. Step 4: Simplify right side
    668.78x = 207,274.58
  5. Step 5: Solve for x
    x = 207,274.58/668.78
  6. Step 6: Final answer
    x = 309.93

Related Problems

Find fourth proportional to 334.39, 501.60 and 103.31
Half scale
Find fourth proportional to 1,337.57, 2,006.42 and 413.22
Double scale
Find fourth proportional to 669.78, 1,004.71 and 207.61
Similar ratio
Find fourth proportional to 1,003.18, 1,504.81 and 309.92
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.