Home / 681.68-940.78-387.05

Finding the Fourth Proportional to 681.68, 940.78 and 387.05

Calculator

Solution

The fourth proportional to 681.68, 940.78 and 387.05 is: 534.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.68 : 940.78 = 387.05 : x
  2. Step 2: Convert to fraction form
    681.68/940.78 = 387.05/x
  3. Step 3: Cross multiply
    681.68x = 940.78 × 387.05
  4. Step 4: Simplify right side
    681.68x = 364,124.68
  5. Step 5: Solve for x
    x = 364,124.68/681.68
  6. Step 6: Final answer
    x = 534.16

Related Problems

Find fourth proportional to 340.84, 470.39 and 193.52
Half scale
Find fourth proportional to 1,363.37, 1,881.56 and 774.09
Double scale
Find fourth proportional to 682.68, 942.16 and 388.05
Similar ratio
Find fourth proportional to 1,022.52, 1,411.17 and 580.57
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.