Xiaohua is going to travel. The suitcase it carries is 40 cm long, 30 cm wide and 60 cm high. Can a 70 cm umbrella be put in?

Solution: diagonal length of trunk bottom = root (40? +30? )=50cm

Diagonal length of trunk = root (50? +60? ) = 10 the square root of 6 1cm ≈ 78. 1cm > 70cm.

So this umbrella can be put in.

Note: The longest connecting line in a cuboid is the body diagonal, and the bottom diagonal is 50cm, so the bottom diagonal is perpendicular to the height, and the length of the body diagonal is obtained by Pythagorean theorem. 78. 1 is the longest connecting line in a cuboid, which is larger than the 70cm length of an umbrella and can be put in.