Question

I need help
Could someone help me please

Answer 1

cos A =
`(5)/(13)`

Explanation:

cos A =
`(adjacent)/(hypotenuse)`

To calculate the hypotenuse AB use Pythagoras' identity

AB² = 15² + 36² = 225 + 1296 = 1521, hence

AB =
`√(1521)` = 39

hence cos A =
`(15)/(39)` =
`(5)/(13)` in simplest form