Question

what is area of one of the blue triangles, like a1? pythagorean theorem a = a1 + a2 + a3 + a4 + a5 (a+b)² = a1 + a2 + a3 + a4 + a5 (a+b)² = a1 + a2 + a3 + a4 + c² 2ab 4ab 1/2 ab a²b²

Explanation:

Step1: Identify Triangle Type

The blue triangles (like A1) are right - angled triangles. For a right - angled triangle, the formula for the area is $\text{Area}=\frac{1}{2}\times\text{base}\times\text{height}$.

Step2: Determine Base and Height

From the diagram, the base of each blue triangle is $a$ and the height is $b$ (or vice - versa, since multiplication is commutative).

Step3: Calculate Area

Using the formula for the area of a right - angled triangle, $\text{Area}=\frac{1}{2}\times a\times b=\frac{1}{2}ab$.

Answer:

$\frac{1}{2}ab$ (corresponding to the option "1/2 ab")