Which relationship in the triangle must be true ?

Choice B. sin(B)=cos(90-B)

Step-by-step explanation:

That cofunction identity is the one you looking for...choice B.

If you aren't convinced or don't know that identity, then maybe this will help:

90-B is actually the same thing as saying A for this right triangle since A+B=90.

So choice B basically says sin(B)=cos(A)

Well let's find both sin(B) and cos(A)

sin(B)=b/c

cos(A)=b/c

Those are the same ratios!

So they are equal!

step-by-step explanation:

answers available in this download

(pearson%2c%25202012)%2520bbs.pdf& usg=aovvaw1obmtxnfghfgxhx0urh_je

step-by-step explanation:

hans did not square the 40-unit side; he merely multiplied it by 2.   incorrect.