In acute triangle △ A B C , ∠ C A B = 3 4 ∘ and E is the foot of the perpendicular from B to A C . A point H on line segment B E is chosen, and X is the foot of the perpendicular from H to A B . What is the measure (in degrees) of ∠ E H X ?
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Nice observation that A E H X is a cyclic quadrilateral.
Consider the quadrilateral AEHX, we know that sum of all the interior angles of a quadrilateral is 360degrees. It is given that E, and X are the perpendiculars, also given that ∠CAB=34degrees. So, ∠EHX=360-[90+90+34] = 146degrees.
XHEA is a quadrilateral and it's given that HX is perpendicular to AB and forms a 90 deg angle, and same goes with HE to AC. Angle A is 34 deg.
The sum of the interior angles of a quadrilateral is 360 deg angle AXH + angle XHE + angle HEA + angle A = 360
90 + angle XHE + 90 + 34 = 360
giving us angle XHE = 146
∠CAB=34°, ∠AEB=90° beacuse line EB is perpendicular to line AC, ∠AXH=90° because line XH is perpendicular to line AB
Supposed, ∠CAB=a ∠AEB=b ∠AXH=c & ∠EHX=d
a+b+c+d=360°
34°+90°+90°+d=360°
d=360°-214°
d=146°
sum of angle of an rectangle is 360 degree, so, angle EHX = 360 - (90 + 90 + 34) = 146
(Angles ABC and ACB are not needed to answer this question) The sum of angles in a Quadrilateral AXHE= 360 degrees. AXHE is a Quadrilateral. Line BE is a perpendicular line so angle AEH=90. Line HX is also a perpendicular so angle AXH is also 90 degrees. Therefore, angle EHX =360-(34+90+90)= 146 degrees.
Good observation that the answer is independent of the values of angles A B C and A C B .
E B A = 9 0 o − 3 4 o = 5 6 o ;
X H B = 9 0 o − 5 6 o = 3 4 o
E H X = 1 8 0 o − 3 4 o = 1 4 6 o
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Since angle AXH = angle AEH = 90 degree, we can conclude that AEHX are vertices of a cyclic quadrilateral.
Hence, since the opposite angles of a cyclic quadrilateral are supplementary, angle EHX = 146 degree