Cos 30° cos 450 -sin 30° sin
1 answer:
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Answer:
The coordinates of the centroid are (0, 5)
Step-by-step explanation:
The coordinates of the centroid of a triangle whose vertices (x1, y1), (x2, y2), and (x3, y3) are ( ,
)
In Δ ABC
∵ A = (-20, 0), B = (0, 15), C = (20, 0)
∴ x1 = -20, x2 = 0, x3 = 20
∴ y1 = 0, y2 = 15, y3 = 0
∴ The centroid = ( ,
) = (
,
) = (0, 5)
∴ The coordinates of the centroid of Δ ABC are (0, 5)
In Δ DBE
∵ D = (-15, 0), B = (0, 15), E = (15, 0)
∴ x1 = -15, x2 = 0, x3 = 15
∴ y1 = 0, y2 = 15, y3 = 0
∴ The centroid = ( ,
) = (
,
) = (0, 5)
∴ The coordinates of the centroid of Δ DBE are (0, 5)
In Δ FBG
∵ F = (-5, 0), B = (0, 15), G = (5, 0)
∴ x1 = -5, x2 = 0, x3 = 5
∴ y1 = 0, y2 = 15, y3 = 0
∴ The centroid = ( ,
) = (
,
) = (0, 5)
∴ The coordinates of the centroid of Δ FBG are (0, 5)
∵ The three triangles are symmetric about the y-axis
→ That means they have the same centroid and it lies on the y-axis
∴ The coordinates of the centroid are (0, 5)