Whats this answer to find the area of the triangle

Me answer number 3plz explain how you do it

Use the squared identities to simplify sin^2x cos^2x

Summary statistics given for independent simple random samples from two populations. use the pooled t-interval procedure to obtain specified confidence interval. x1=71.6, s1=3.9, n1=11, x2=67.9, s2=3.4, n2=9 determine a 99% confidence level.