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Friday, April 10, 2009

Rosyth Sch 2006 PSLE Math Prelim Q41

In the figure below, AB is parallel to DE and ACDG is parallel to EF. ABC is an isosceles triangle with Angle ABC = 36 degrees. Find Angle DEF.



Solution

Angle BAC ---- (180 – 36) degrees divided 2 = 72 degrees
Angle EDG ----- 72 degrees
Angle DEF ----- (180 – 72) degrees = 108 degrees (Answer)

4 comments:

Flawless said...

Hi,

I have been wondering who could be the setter for this question.

Base on what i have observed at the figure, i have notice that the figure has a flawed.

How can angle BAC = angle BCA when
angle BAC is more than angle BAC at first glance.

Flawless said...

Hi,

I have been wondering who could be the setter for this question.

Base on what i have observed at the figure, i have notice that the figure has a flawed.

How can angle BAC = angle BCA when
angle BAC is more than angle BCA at first glance.

Anonymous said...

Why is angle EDG 72 degrees?

ExcelEduservice said...

Angle BAC is 72 deg

AB and DE are parallel lines

ACDG is a straight line.

Therefore,
Angle BAC = Angel EDG = 72 deg
(corresponding angles)