Home / 712.80-984.15-664.20

Finding the Fourth Proportional to 712.80, 984.15 and 664.20

Calculator

Solution

The fourth proportional to 712.80, 984.15 and 664.20 is: 917.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.80 : 984.15 = 664.20 : x
  2. Step 2: Convert to fraction form
    712.80/984.15 = 664.20/x
  3. Step 3: Cross multiply
    712.80x = 984.15 × 664.20
  4. Step 4: Simplify right side
    712.80x = 653,672.43
  5. Step 5: Solve for x
    x = 653,672.43/712.80
  6. Step 6: Final answer
    x = 917.05

Related Problems

Find fourth proportional to 356.40, 492.08 and 332.10
Half scale
Find fourth proportional to 1,425.60, 1,968.30 and 1,328.40
Double scale
Find fourth proportional to 713.80, 985.53 and 665.20
Similar ratio
Find fourth proportional to 1,069.20, 1,476.23 and 996.30
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.