AC Lim's answer to Jan's Primary 6 Maths Measurement Singapore question.
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Area of each unshaded parts are equal.
Therefore, 118 ÷ 2 = 59
Area of 1 triangle include the shaded part = ½×10×14=70
So, shaded parts = 70-59=11cm².
Hope this helps.
Therefore, 118 ÷ 2 = 59
Area of 1 triangle include the shaded part = ½×10×14=70
So, shaded parts = 70-59=11cm².
Hope this helps.
Date Posted:
4 years ago
I hope this is correct
It is correct.
A slightly different way to do this question:
Since the triangles are identical, we can tell from the info of both triangles that the height is 10cm and base is 14cm.
Area of 2 identical triangles
= 2 x (½ x base x height)
= 2 x ½ x 10cm x 14cm
= 10cm x 14cm
= 140cm²
Now,
Left unshaded part + 1 shaded part = 1 triangle.
Right unshaded part + 1 shaded part
= the other triangle (same area as the first)
Add them together,
All the unshaded parts + 2 shaded parts = 2 triangles area
So 2 shaded parts = 2 triangles area - all the unshaded parts
= 140cm² - 118cm²
= 22cm²
1 unshaded part = 22cm² ÷ 2 = 11cm²
A slightly different way to do this question:
Since the triangles are identical, we can tell from the info of both triangles that the height is 10cm and base is 14cm.
Area of 2 identical triangles
= 2 x (½ x base x height)
= 2 x ½ x 10cm x 14cm
= 10cm x 14cm
= 140cm²
Now,
Left unshaded part + 1 shaded part = 1 triangle.
Right unshaded part + 1 shaded part
= the other triangle (same area as the first)
Add them together,
All the unshaded parts + 2 shaded parts = 2 triangles area
So 2 shaded parts = 2 triangles area - all the unshaded parts
= 140cm² - 118cm²
= 22cm²
1 unshaded part = 22cm² ÷ 2 = 11cm²
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