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secondary 2 | Maths
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Please help me solve for angles ABY and CDY. Thanks!
So AB = BC = CD = AD and the 4 angles are all right angles (90°)
AC is the diagonal of the square, and it divides the square into 2 isosceles right-angled triangles ABC and ADC.
∠CAB = ∠BCA = 45° , they are base angles of the same isosceles triangle since AB = BC
( Or (180° - 90°)/2 = 45°)
∠YAB = ∠CAB - 19°
= 45° - 19°
= 26°
Since AB = AY, triangle ABY is isosceles
∠ABY = ∠AYB (base angles of the same isosceles triangle)
∠ABY = (180° - ∠YAB)/2
= (180° - 26°)/2
= 154° / 2
= 77°
Then AY = AD
So triangle AYD is also isosceles.
∠AYD = ∠ADY (base angles of the same isosceles triangle)
∠DAY = ∠DAC + ∠ CAY
= 45° + 19°
= 64°
∠AYD = (180° - 64°)/2 = 58°
∠CDY = ∠ADC - ∠AYD
= 90° - 58°
= 32°
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