If sides A and B of a triangle have lengths of 8 and 3 respectively, and the angle between them is #(5pi)/8#, then what is the area of the triangle? Trigonometry Triangles and Vectors Area of a Triangle 1 Answer Veddesh #phi# Oct 2, 2016 #11.09# Explanation: #"Let's consider the diagram"# #"I have mentioned"# #(5pi)/8# #"as"# #112.5^circ# #"We can find the area of a triangle given the length of two sides"# #"and the angle between them using this formula"# #color(blue)(##color(blue)("Area"##color(blue)(=1/2*"##color(blue)("A"##color(blue)(*##color(blue)("B"##"color(blue)(*sin(c)# #rarr1/2*8*3*sin(112.5)# #rarr1/cancel2^1*cancel24^12*sin(112.5)# #rarr12*sin(112.5)# #rarr12*0.92# #color(green)(rArr11.09# Answer link Related questions How do you find the area of a triangle with 3 sides given? What is the area of a equilateral triangle with a side of 12? How do you find the area of a triangleABC, if #angleC = 62^@#, #b = 23.9# , and #a = 31.6#? How do you find the area of a triangleGHI, if #angleI = 15^@#, #g = 14.2# , and #h = 7.9#? What is Heron's formula? When do you use Heron's formula to find area? How do you find the area of a triangle ABC, if #a = 23#, #b = 46# , and #c = 41#? Question #f2e4c How do you find the area of the triangle given c= 4, A= 37 degrees, B= 69 degrees? How do you find the area of the triangle given C=85 degrees, a= 2, B= 19 degrees? See all questions in Area of a Triangle Impact of this question 2111 views around the world You can reuse this answer Creative Commons License