Use worked examples to understand percentages, averages, grades, ratios, and practical conversions. Try the percentage calculator, GPA calculator, or unit converter. Grade and GPA rules depend on the selected scale and your institution.
One cubic foot equals approximately 7.48052 US liquid gallons or 6.22884 imperial gallons. Multiply cubic feet by the appropriate factor. Always label the gallon system so the result cannot be mistaken for a different capacity.
A reverse percentage works backward from a final amount to the amount before a percentage change. Divide by the percentage multiplier: original = final ÷ (1 + rate) after an increase, or original = final ÷ (1 − rate) after a decrease. Write the rate as a decimal.
A semester GPA summarizes the eligible graded courses in one semester. A cumulative GPA combines the eligible graded courses across the relevant terms. When terms have different credit loads, the cumulative figure is a credit-weighted average, not a simple average of the term GPAs.
The distance between two points on a flat coordinate plane is d = √[(x₂ − x₁)² + (y₂ − y₁)²]. Subtract the horizontal coordinates, subtract the vertical coordinates, square both differences, add them and take the square root.
Use this GPA-to-letter-grade reference for quick estimates, then check your school’s official grading policy before making decisions.
Learn the weighted-average formula with worked examples for grades, prices, and portfolio returns, plus the mistakes that change the answer.
A shipping quote for a two-kilogram lampshade shouldn’t cost as much as one for an eight-kilogram box – except sometimes it does, and the reason is dimensional weight. Carriers charge based on whichev…
An apartment advertised as “1,000 sq ft” might only give you around 700-750 sq ft you can actually furnish. That’s not a scam – it’s three different area measurements getting compressed into one marke…
Two students, both with a 4.0. One took every easy elective available. The other took a full load of Advanced Placement courses and still landed at exactly 4.0. Unweighted GPA can’t tell them apart – …
The tablet spins around, and suddenly you’re picking from three suggested tip percentages at a counter where nobody expected a tip a few years ago. Those numbers aren’t neutral – they’re a default set…
