An isosceles triangle is pictured below.
Determine the value of \(a^{\circ}\), giving reasons for your answer. (2 marks)
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\(b^{\circ} = 180-95=85^{\circ}\ \ \text{(180° in straight line)} \)
\(\text{Isosceles triangle}\ \ \Rightarrow\ \ \text{angles opposite equal sides are equal}\)
| \(2a^{\circ}\) | \(=85\ \ \text{(external angle = sum of interior opposite angles)} \) | |
| \(a^{\circ}\) | \(= \dfrac{85}{2}\) | |
| \(=42.5^{\circ}\) |
Show Worked Solution
\(b^{\circ} = 180-95=85^{\circ}\ \ \text{(180° in straight line)} \)
\(\text{Isosceles triangle}\ \ \Rightarrow\ \ \text{angles opposite equal sides are equal}\)
| \(2a^{\circ}\) | \(=85\ \ \text{(external angle = sum of interior opposite angles)} \) | |
| \(a^{\circ}\) | \(= \dfrac{85}{2}\) | |
| \(=42.5^{\circ}\) |