Home / 408.21-612.15-191.64

Finding the Fourth Proportional to 408.21, 612.15 and 191.64

Calculator

Solution

The fourth proportional to 408.21, 612.15 and 191.64 is: 287.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.21 : 612.15 = 191.64 : x
  2. Step 2: Convert to fraction form
    408.21/612.15 = 191.64/x
  3. Step 3: Cross multiply
    408.21x = 612.15 × 191.64
  4. Step 4: Simplify right side
    408.21x = 117,312.43
  5. Step 5: Solve for x
    x = 117,312.43/408.21
  6. Step 6: Final answer
    x = 287.38

Related Problems

Find fourth proportional to 204.11, 306.08 and 95.82
Half scale
Find fourth proportional to 816.42, 1,224.30 and 383.28
Double scale
Find fourth proportional to 409.21, 613.65 and 192.64
Similar ratio
Find fourth proportional to 612.32, 918.23 and 287.46
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.