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Or

Using Geometry, find the value of sin 60°.

Sol.

Δ ABC be an equilateral, Let each side be 2a. Since each angle in equilateral Δ is 60°

Q. 21. Show that the points (1, 1), (–1, 5), (7, 9) and (9, 5) taken in that order, are the vertices of a rectangle.

Sol. Let A(1, 1), B(– 1, 5), C(7, 9) and D(9, 5) Using Distance formula

Diagonal AC = Daigonal BD = 10
∴ Diagonals are equal …(ii)
From (i) and (ii), we get
Points A, B, C and D are the vertices of a rectangle.

Mathematics 2009 Question Papers Class X
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