Home / 681.09-939.88-386.40

Finding the Fourth Proportional to 681.09, 939.88 and 386.40

Calculator

Solution

The fourth proportional to 681.09, 939.88 and 386.40 is: 533.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.09 : 939.88 = 386.40 : x
  2. Step 2: Convert to fraction form
    681.09/939.88 = 386.40/x
  3. Step 3: Cross multiply
    681.09x = 939.88 × 386.40
  4. Step 4: Simplify right side
    681.09x = 363,169.63
  5. Step 5: Solve for x
    x = 363,169.63/681.09
  6. Step 6: Final answer
    x = 533.22

Related Problems

Find fourth proportional to 340.55, 469.94 and 193.20
Half scale
Find fourth proportional to 1,362.18, 1,879.76 and 772.80
Double scale
Find fourth proportional to 682.09, 941.26 and 387.40
Similar ratio
Find fourth proportional to 1,021.64, 1,409.82 and 579.60
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.