The flag of Czechia consists of two horizontal stripes and a blue isosceles triangle, with an aspect ratio of 2:3. The upper stripe is white (color code #FFFFFF), the lower stripe is red (#D7141A), and the blue triangle (#11457E) extends from the hoist side to the center of the flag.

For the triangle, its base is along the vertical edge at the hoist, and its vertex touches the midpoint of the opposite side. In terms of measurements, if we assume the height of the flag to be 'h' and the width 'w', then:

• Aspect ratio: w = 1.5h
• White stripe height: 0.5h
• Red stripe height: 0.5h
• Blue triangle base: h
• Blue triangle height: 0.5w

Since there are no other patterns, symbols, or complex geometric shapes, these are the key geometric properties and measurements of the flag.