Two $4\times4$ squares intersect as shown. At each intersection, their crossing sides are perpendicular and bisect each other. Draw a circle whose diameter joins the two intersection points. What is the area of the shaded region?
A gum machine contains $9$ red, $7$ white, and $8$ blue pieces of gum, dispensed randomly. What is the minimum number of purchases that guarantees four pieces of the same color?
Alex and Bob run around rectangle ABCD. Alex starts at A toward D at 30 metres per minute; Bob starts at B toward C at 42 metres per minute. They first meet after 3 minutes and meet again 4 minutes later. Find the perimeter.
In the diagram, $ABCD$ is a rectangle and $EFGH$ is a parallelogram. Using the labeled lengths, find the perpendicular distance $d$ between $HE$ and $FG$.
Bình (B), Đức (Đ), Hoa (H), and Lan (L) stand in line for ice cream. The person in the third position stands between Hoa and Bình. Đức stands immediately before Hoa, and Hoa is not last. What is their order?
Samantha lives at the lower-left corner and her school is at the upper-right corner of the illustrated map. She follows the two directions indicated by the compass. How many routes can she take?
Triangle $ABC$ has area $8$ square meters. Points $M$ and $N$ are the midpoints of $AB$ and $AC$, respectively. Altitude $AD$ bisects $BC$. What is the shaded area?
Each half of the diagram contains $3$ red, $5$ blue, and $8$ white triangles. When the upper half is folded down along the horizontal line, two red-red pairs, three blue-blue pairs, and two red-white pairs overlap. How many white-white pairs overlap?