Home / 392.80-542.20-261.81

Finding the Fourth Proportional to 392.80, 542.20 and 261.81

Calculator

Solution

The fourth proportional to 392.80, 542.20 and 261.81 is: 361.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.80 : 542.20 = 261.81 : x
  2. Step 2: Convert to fraction form
    392.80/542.20 = 261.81/x
  3. Step 3: Cross multiply
    392.80x = 542.20 × 261.81
  4. Step 4: Simplify right side
    392.80x = 141,955.39
  5. Step 5: Solve for x
    x = 141,955.39/392.80
  6. Step 6: Final answer
    x = 361.40

Related Problems

Find fourth proportional to 196.40, 271.10 and 130.91
Half scale
Find fourth proportional to 785.60, 1,084.41 and 523.63
Double scale
Find fourth proportional to 393.80, 543.58 and 262.81
Similar ratio
Find fourth proportional to 589.20, 813.30 and 392.72
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.