Home / 628.80-867.64-392.71

Finding the Fourth Proportional to 628.80, 867.64 and 392.71

Calculator

Solution

The fourth proportional to 628.80, 867.64 and 392.71 is: 541.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    628.80 : 867.64 = 392.71 : x
  2. Step 2: Convert to fraction form
    628.80/867.64 = 392.71/x
  3. Step 3: Cross multiply
    628.80x = 867.64 × 392.71
  4. Step 4: Simplify right side
    628.80x = 340,724.60
  5. Step 5: Solve for x
    x = 340,724.60/628.80
  6. Step 6: Final answer
    x = 541.86

Related Problems

Find fourth proportional to 314.40, 433.82 and 196.35
Half scale
Find fourth proportional to 1,257.60, 1,735.27 and 785.41
Double scale
Find fourth proportional to 629.80, 869.01 and 393.71
Similar ratio
Find fourth proportional to 943.20, 1,301.45 and 589.06
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.