By trigonometry, lengths and angles are calculated for a right angled triangle when only two values are known (at least one must be a length). The triangle's area and perimeter are also calculated. A proportionally correct triangle is drawn after the calculations. The triangle can be rotated and mirrored. The number of decimals for lengths, angles and area can be specified. Possibility to reuse and edit the last specified values after clearing. Possibility to change the color theme on background