Question

What is the area of the isosceles triangle whose base is 10 and its base angle is 60 degree

Answer 1

Answer:

Answer:

Area of triangle = 109.36 cm²

Step-by-step explanation:

For better explanation of the solution see the attached figure :

Given : BC = 16 cm and ∠A = 60° 40'

⇒ ∠A = (60 + 40 × 0.0167)°

⇒ ∠A = 60.67°

Since, ΔABC is an isosceles triangle

⇒ AB = AC

⇒ ∠B = ∠C ( angle opposite to equal sides are equal)

Using angle sum property of triangle,

∠A + ∠B + ∠C = 180

⇒ 2∠B = 119.33

⇒ ∠B =59.665°

Now, draw a perpendicular D from A on BC

⇒ BD = BC = 8 cm

\begin{gathered}\tan 59.665=\frac{AD}{BD}\\\\\implies AD = 13.67\end{gathered}

tan59.665=

BD

AD

⟹AD=13.67

Base = 16 cm and Height = 13.67

\begin{gathered}Area=\frac{1}{2}\times base\times height\\\\\implies Area=\frac{1}{2}\times 16\times 13.67\\\\\implies Area=109.36\text{ square cm}\end{gathered}

Area=

2

1

×base×height

⟹Area=

2

1

×16×13.67

⟹Area=109.36 square cm

Answer 2

Answer:

60 degree is the correct answer

Step-by-step explanation:

60 +60+60+=180 degree