Question

Find the missing side or angle.

Round to the nearest tenth.
b=15 a=30 c=29 a=[?]. Acellus plz

Answer 1

∠ A ≈ 79.0°

Explanation:

Using the Cosine rule to find the angle

cosA =
`(b^2+c^2-a^2)/(2bc)`

=
`(15^2+29^2-30^2)/(2(15)(29))`

=
`(225+841-900)/(870)`

=
`(166)/(870)` , then

A =
`cos^(-1)` (
`(166)/(870)` ) ≈ 79.0° ( to the nearest tenth )