Question

In the figure given below, ABC = 45°, ACB = 120° and BC = 20 cm. AD is drawn perpendicular on BC such that it meets BC produced at D. Find the length (in cm) of AD.​

Answer 1

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• Angle A is given as 120°

• When a perpendicular is drawn on BC, it bisects the angle A in two equal halves( forming two angles each 60°)

• So now considering the smaller triangle, ADC, we have angle DAC = 60° and angle ADC as 90°

• So, angle ACD comes as 180-( 60°+90°) = 30° [ Sum of all the three angles of a triangle is 180°].

• Therefore, we get angle C as 30°.

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Answer 2

Answer:

length(in cm) of AD= 10(3+✓3)