Solve any equation forward or backward—click any variable to make it the target with automatic SI unit conversions.
Solve a² + b² = c² for the hypotenuse c or either orthogonal leg a or b of a right triangle.
Solve Δ = b² - 4ac for the quadratic discriminant Δ or any coefficient a, b, or c in ax² + bx + c = 0.
Solve A = (θ / 360) × π × r² for circular or sector area, radius r, or central angle θ (set θ = 360° for a full circle).
Solve V = (4/3) × π × (R³ - r³) for solid or hollow sphere volume, outer radius R, or inner cavity radius r (set r = 0 for a solid sphere).
Solve V = π × r² × h for right circular cylinder volume, cylinder radius r, or axial height/length h.
Solve V = (1/3) × π × r² × h for right circular cone volume, base radius r, or vertical apex height h.
Solve a_n = a₁ + (n - 1)d for the n-th term, first term a₁, term index n, or common difference d.
Solve a_n = a₁ × r^(n - 1) for the n-th geometric term, initial term a₁, common ratio r, or term index n.
Bidirectionally solve y = b^x ⇔ x = log_b(y) for the exponential result y, logarithm exponent x, or base b.
Solve c² = a² + b² - 2ab cos(C) for any triangle side c, a, b or the included angle C in degrees.
Solve a / sin(A) = b / sin(B) for side a, side b, opposite angle A, or opposite angle B.
Solve Heron's formula A = √(s(s-a)(s-b)(s-c)) for triangle area A or any side length a, b, or c.
Solve θ = ((n - 2) × 180) / n for the single interior vertex angle θ or the number of polygon sides n.
Solve d = √(Δx² + Δy²) for straight-line Euclidean distance d, horizontal coordinate delta Δx, or vertical coordinate delta Δy.
Solve the Golden Section S = a + b = φ × a for total span S, major segment a, or minor segment b.
Solve PE = ((E - T) / T) × 100 for signed percent error, experimental measured value E, or theoretical true value T.
Solve Euclidean division N = d × q + r for remainder r (N mod d), dividend N, divisor d, or integer quotient q.
Solve HM = 3 / (1/a + 1/b + 1/c) for the harmonic mean of three rates/multiples, or solve backwards for the required third value c.