Considere um triângulo retângulo, cujos ângulos agudos a e b satisfazem à condição cos a = 0,8 e cos b = 0,6 Determine a área desse triângulo, em cm² sabendo que o comprimento da hipotenusa é 5 cm. a) 4,5
b) 6
c) 7,5
d) 8
e) 10

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations