Answer:
417
Explanation:
Lian is making a banner for the school gym. She cut three pieces of fabric into congruent isosceles triangles, as shown.
3 isosceles triangles are connected to a pole by their base. The length of the bases is 20.5 inches. The length of the sides are 17 inches. The angle opposite to the base is 74 degrees.
Trigonometric area formula: Area = One-half a b sine (C)
To the nearest square inch, how much fabric will she use to make all three triangles?
139 square inches
172 square inches
417 square inches
515 square inches