Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2017-part-01 — 176 problems (EN–VI) Question 96

Math Olympiad Vault · MathNet 2017-part-01 — 176 problems (EN–VI)

Question 96

In the drawing below, $ABCD$ and $EFGC$ are squares. The lines $BG$ and $DE$ meet at the point $H$.
a) Verify that $\angle BHD = 90^\circ$ and conclude that the point $H$ lies simultaneously on the circles with diameters $BD$ and $EG$.
b) Find the value of $\angle AHD + \angle DHG + \angle GHF$.
Question illustration