The isosceles

The isosceles trapezoid ABCD has bases of 18 cm and 12 cm. The angle at apex A is 60°. What is the circumference and content of the trapezoid?

Correct answer:

o =  42 cm
S =  77.9423 cm2

Step-by-step explanation:

a=18 cm c=12 cm α=60 °  x=(ac)/2=(1812)/2=3  cosα=x:b  b=x/cosα°=x/cos60° =3/cos60° =3/0.5=6 cm d=b=6 cm  o=a+b+c+d=18+6+12+6=42 cm
h=b sinα°=b sin60° =6 sin60° =6 0.866025=5.19615 cm S=a+c2 h=18+122 5.1962=45 3=77.9423 cm2



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