Can you judge by just looking?

$\text{Area of Yellow triangle} \to \frac{base \times height}{2} = \frac{80 \times height}{2} \\ \text{where height =} \sqrt{41^2 - 40^2} \color{#3D99F6} \text{ (By the Pythagorean theorem)} \color{#20A900} \to 9 \\ \therefore \text{Area of the yellow triangle } \to \frac{80 \times 9}{2} \\ \large \color{magenta}= 360$

$\text{Area of Red triangle} \to \frac{base \times height}{2} = \frac{18 \times height}{2} \\ \text{where height =} \sqrt{41^2 - 9^2} \color{#3D99F6} \text{ (By the Pythagorean theorem)} \color{#20A900} \to 40 \\ \therefore \text{Area of the red triangle } \to \frac{18 \times 40}{2} \\ \large \color{magenta}= 360$

$\large \text{Hence, the 2 areas are} \color{#EC7300} \text{ EQUAL. }$

Consider the yellow triangle:

$s=\dfrac{41+41+80}{2}=81$

$A_{yellow}=\sqrt{81(81-41)(81-41)(81-80)}=360$

Consider the red triangle:

$s=\dfrac{41+41+18}{2}=50$

$A_{red}=\sqrt{50(50-41)(50-41)(50-18)}=360$

Hence, the areas are equal.

heron s formula as sides are equal areas are equal