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kramer
3 years ago
9

An equilateral triangle with side length 7 cm is shown in the diagram, work out the area of the triangle.

Mathematics
1 answer:
ElenaW [278]3 years ago
8 0
If a triangle has sides of 7 cm and it is an equilateral you can draw a line right down the middle to form two congruent triangles.

These smaller triangles have a hypotenuse of 7cm and a base of 3.5 cm (7/2)

To work out the height, use Pythagoras’ theorem.

a^2 + b^2 = c^2 where c is the hypotenuse and a and b are the other two sides

7^2 - 3.5^2 = 36.75

Square root answer

= 6.06 cm

That’s the height of the triangle

Area of a triangle is base x height divided by 2

So 7 x 6.06 = 42.43…

/2

= 21.2 cm^2 to one d.p

Hope this helped!
Please mark Brainliest!!
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