Δdef is an isosceles triangle with base angles e and f. what is the angle measure of the smallest angle in the triangle? approximate to the nearest degree. degrees

We have ∠D, ∠E, and ∠F and side , side , and side  as shown in the diagram below

by Cosine rule, we work out the angle D









rounded to 2 dp

Triangle DEF is an isosceles triangle, so we can work out ∠E and ∠F by using the angles in triangle rules

180°-14.36 = 165.64°
165.64°÷2=82.9° rounded to 1 dp

so now we have
∠D = 14.36
∠E = ∠F = 82.9

Smallest angle is angle D