2025 AMC 10A Problems/Problem 21
Let
be a square with side length 10. Points
and
lie on sides
and
, respectively, such that
. Let
be the intersection of segments
and
.
What is the area of triangle
?
Solution
We can find the area of
by finding its base and height.
- Base:

- Height: To find the height, we can use similar triangles.
- So,

- Substituting the values, we get:

- Solving for
, we get
.
Therefore, the area of $\triangle APR = \frac{1}{2} \cdot base \cdot height = \frac{1}{2} \cdot 2 \cdot \frac{5}{3} = \textbf{(B)}\ 5/3 \qquad\