Home / 663.90-990.08-656.70

Finding the Fourth Proportional to 663.90, 990.08 and 656.70

Calculator

Solution

The fourth proportional to 663.90, 990.08 and 656.70 is: 979.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.90 : 990.08 = 656.70 : x
  2. Step 2: Convert to fraction form
    663.90/990.08 = 656.70/x
  3. Step 3: Cross multiply
    663.90x = 990.08 × 656.70
  4. Step 4: Simplify right side
    663.90x = 650,182.25
  5. Step 5: Solve for x
    x = 650,182.25/663.90
  6. Step 6: Final answer
    x = 979.34

Related Problems

Find fourth proportional to 331.95, 495.04 and 328.35
Half scale
Find fourth proportional to 1,327.80, 1,980.15 and 1,313.40
Double scale
Find fourth proportional to 664.90, 991.57 and 657.70
Similar ratio
Find fourth proportional to 995.85, 1,485.11 and 985.05
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.