A circle with its centre in the origin is cut by two parallel lines that are a distance d apart. One line is passing through the leftmost and one through the lowest point of the circle. What is the area of the green trapezium in terms of d?

Solution

The green area is d².

Poem

The green trap is here
Staying so close, so near
We’ll pick the leaves
In the pale leaves with dew
Fallen from the trees at autumn
Searching for a treasure
Under the sun and sky so blue
The heart breathes hopefully
It is a promise for the future
A promise for life and tree

Bella