AC Lim's answer to Ricky's Primary 5 Maths Angles & Geometry Singapore question.
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Hope this helps
Date Posted:
4 years ago
Area ADE should be 1/2 X AD X DE and not 1/2 X AD X DC.
Is 1/2 x AD x dotted line (90 deg with AD )
Dotted line = DC = 24 since it is square.
(Triangle Area = 1/2 x base x height. Base and height should be perpendicular, 90deg) Hope this clear your doubts.
Dotted line = DC = 24 since it is square.
(Triangle Area = 1/2 x base x height. Base and height should be perpendicular, 90deg) Hope this clear your doubts.
At the same time, area ADE also = 1/2 x AE x yellow line (perpendicular height)
Yellow line = AG. Where you can find Length AG.
Yellow line = AG. Where you can find Length AG.
Ricky, area of a triangle is
1/2 x base x perpendicular height
Note the word “perpendicular”. That is, the height chosen must be at right angles (90 degrees) to your chosen base. Lengths DE and AD are not at 90 degrees to each other considering that ABCD is a square.
So it is obviously not 1/2 x AD x DE.
AC Lim’s workings are fully correct.
1/2 x base x perpendicular height
Note the word “perpendicular”. That is, the height chosen must be at right angles (90 degrees) to your chosen base. Lengths DE and AD are not at 90 degrees to each other considering that ABCD is a square.
So it is obviously not 1/2 x AD x DE.
AC Lim’s workings are fully correct.
360 Tutoring Program