Bunuel
What is the value of a?
(1) The area of an equilateral triangle of side length 3a units is \(9\sqrt{3}\) square units
(2) The area of an isosceles triangle whose sides are of length 4a, 4a and a units is \(3\sqrt{7}\) square units
Solution
Step 1: Analyse Question Stem
We need to find the value of \(a\).
Step 2: Analyse Statements Independently (And eliminate options) – AD/BCE
Statement 1: The area of an equilateral triangle of side length \(3a\) units \(9√3\) square units.
• With this information we will get an equation of one variable a, and we will take the only positive value of a.
o Indirectly we can infer that we can find the value of a.
• We don’t need to solve it but for the sake of clarity am showing you.
o \(\frac{√3}{4}*(3a)^2= 9√3\)
o \(a^2 = 4\)
\(a =2,\) we have discarded the case of -2 because the length can never be negative.
Hence, statement 1 is sufficient, we can eliminate answer options B, C, and E.
Statement 2: The area of an isosceles triangle whose sides are of 4a, 4a and a unit 3√7 square units.
• We can find, the height of the triangle in terms of a, and we can form an equation in terms of a and after comparing with the given value of the area, we can find the value of a.
Hence, statement 2 is also sufficient, the correct answer is
Option D.