Question 170580
A  rhombus has sides of length 6 cm. One of its diagonals is 10 cm long. Find the length of the other diagonal ?

The sides of a rhombus are the same measure.

One diagonal measures 10m.  This means that it is 5m + 5m.

The two diagonals meet and form right angles.

We can use the Pythagorean Theorem to find one leg of one of the right triangles formed inside the rhombus.

5^2 + x^2 = 6^2

25 + x^2 = 36

x^2 = 36 - 25

x^2 = 11

Take the square root of both sides.

x = sqrt{11}.

The other diagonal will be sqrt{11} + sqrt{11) = 2sqrt{11}m

Did you follow?