Home / 646.40-969.64-213.60

Finding the Fourth Proportional to 646.40, 969.64 and 213.60

Calculator

Solution

The fourth proportional to 646.40, 969.64 and 213.60 is: 320.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.40 : 969.64 = 213.60 : x
  2. Step 2: Convert to fraction form
    646.40/969.64 = 213.60/x
  3. Step 3: Cross multiply
    646.40x = 969.64 × 213.60
  4. Step 4: Simplify right side
    646.40x = 207,115.10
  5. Step 5: Solve for x
    x = 207,115.10/646.40
  6. Step 6: Final answer
    x = 320.41

Related Problems

Find fourth proportional to 323.20, 484.82 and 106.80
Half scale
Find fourth proportional to 1,292.80, 1,939.28 and 427.20
Double scale
Find fourth proportional to 647.40, 971.14 and 214.60
Similar ratio
Find fourth proportional to 969.60, 1,454.46 and 320.40
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.