Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.



Question

secondary 2 | Maths
3 Answers Below

Anyone can contribute an answer, even non-tutors.

Answer This Question
Adwin
Adwin

secondary 2 chevron_right Maths chevron_right Singapore

Hi, I am stuck at part e of the question. Can anyone help? The answer is 4.2 cm², but I am not sure why and how.

Date Posted: 4 years ago
Views: 266
Ong Ming Yuan
Ong Ming Yuan
4 years ago
Yup.

Draw a line perpendicular to BK which hits point D.

That is the height of Triangle BDK.

You can extend the that line to the left until it hits the the line parallel to BK.

Note that the two parallelograms are identical to each other.
Ong Ming Yuan
Ong Ming Yuan
4 years ago
Hello Adwin.

If you have the solution to the question, could you post it so i can see it?

Thanx.

Yuan.
Adwin
Adwin
4 years ago
Sorry, I do not have the solution as the paper only has the final answer of 4.8 cm².

My final working, based on your help is as follows:

Area of ΔJFK / Area of ΔBDK = (3 / 9)²
2.4 / Area of ΔBDK = 1 / 9
Area of ΔBDK = 21.6 cm²

Height of ΔBDK = 21.6 cm² / 9cm × 2
= 4.8 cm

Height of ΔBDK = Height of ΔGFK = 4.8 cm

Area of ΔGFK = ½ × 4.8 cm × 3 cm
= 7.2 cm²

Area of ΔGJF = Area of ΔGFK - Area of ΔJFK
= 7.2 cm² - 2.4 cm²
= 4.8 cm²
Ong Ming Yuan
Ong Ming Yuan
4 years ago
Thanx, Adwin.

See 3 Answers

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Ong Ming Yuan
Ong Ming Yuan's answer
28 answers (A Helpful Person)
1st
Part 1 of 2.
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Ong Ming Yuan
Ong Ming Yuan's answer
28 answers (A Helpful Person)
Part 2 of 2.
Adwin
Adwin
4 years ago
Thanks. Can you explain the part about triangles BDK and HGF having similar heights? I don't see it.
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Ong Ming Yuan
Ong Ming Yuan's answer
28 answers (A Helpful Person)
Basically how I come to the conclusion the heights are the same.