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The area (in cm2) of an equilateral triangle whose height is 6 cm, is:
493
63
233
123
123
For an equilateral triangle, Area = h² / √3. Since h = 6, Area = 36/√3 = 12√3.
Height of the equilateral triangle h = 6 cm.
Area=3h2
For an equilateral triangle, Area = h² / √3. Since h = 6, Area = 36/√3 = 12√3.
Many students try to use (1/2) * base * height and get stuck because the base is not directly provided, requiring extra steps to find it from the height.
Identify given parameters
The height of the equilateral triangle is given as h=6 cm.
h=6
Apply Area formula
The area of an equilateral triangle in terms of its height h is given by the formula Area=3h2.
Area=3h2
Calculate the Area
Substitute h=6 into the formula: Area=362=336. To rationalize, multiply the numerator and denominator by 3.
Area=336×33=3363=123
D is correct because the calculation 123 matches option D.
This formula A=h2/3 is derived from the standard area formula A=(3/4)a2 by substituting the side length a=2h/3, which is a very useful time-saver in geometry problems.