Home / 987-1,478.76-438.18

Finding the Fourth Proportional to 987, 1,478.76 and 438.18

Calculator

Solution

The fourth proportional to 987, 1,478.76 and 438.18 is: 656.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    987 : 1,478.76 = 438.18 : x
  2. Step 2: Convert to fraction form
    987/1,478.76 = 438.18/x
  3. Step 3: Cross multiply
    987x = 1,478.76 × 438.18
  4. Step 4: Simplify right side
    987x = 647,963.06
  5. Step 5: Solve for x
    x = 647,963.06/987
  6. Step 6: Final answer
    x = 656.50

Related Problems

Find fourth proportional to 493.50, 739.38 and 219.09
Half scale
Find fourth proportional to 1,974, 2,957.52 and 876.36
Double scale
Find fourth proportional to 988, 1,480.26 and 439.18
Similar ratio
Find fourth proportional to 1,480.50, 2,218.14 and 657.27
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.