Answer:
x² = 900
Step-by-step explanation:
ΔABC is an equilateral triangle because its sides are equal lengths
this means their angles are also equal.
180 / 3 = 60
∠BCA and ∠DCA are supplementary angles - add up to 180º
if ∠BCA = 60º, then ∠DCA = 120º
ΔACD is an isosceles triangle because two sides are equal lengths. this means their angles are equal.
∠CAD ≅ ∠CDA
180 - ∠DCA = 2(∠CAD)
180 - 120 = 60
60 / 2 = 30º
x = 30º
x² = 900
