Hello, skitty!

Here's the first one . . .

[quote]1. Prove that the triangles in the diagram are both right triangles.Code:Q o * * * * * * * * * * * * * * * * * P o * * * * * * * * * o R * * * * * * * * * * * * * * * o * * S

We are given: .

Since

Then: .[1]

And: .[2]

Add [1] and [2]: .

. . That is: .

Since , then: .

Since are inscribed in semicircles,