The triangle ABC have two equal sides where AB = 10 cm, And BC = 10 cm, what Is the length of CA?

1 Answer
May 21, 2015

There is no single answer for this question.

The side CA can have any length between 0 and 20 cm. To calculate the exact length more data is needed. The task is in Trigonometry, so probably the angle is missing.

For example:

Suppose you have an angle B

If the angle was 60 degrees, all sides would be equal, so |CA|=10
However if the angle was 90 degrees, the CA would be a hypothenuse and would be 102 cm long.

Generally if the angle was α you could calculate a general formula using law of cosines.

|CA|2=|CB|2+|AB|22|CB||AB|cosα, so

|CA|=|CB|2+|AB|22|CB||AB|cosα