Question

A diagonal of a cube measures 15 cm and the length of an edge of the cube is 75 cm. What is the length of the diagonal of a face of the cube? Round to the nearest tenth
7.1 cm A
12.2 cm B
13 cm C (PLZ HELP WILL GIVE BRAINLIEST!!!!)
15 cm D

Answer 1

The answer to your question is B have a nice day boyo.

Answer 2

Answer:  The correct option is (C) 13 cm.

Step-by-step explanation:  As shown in the attached figure below, PR is a diagonal of the cube, PQ is an edge and QR is the diagonal of one of the faces of the cube.

PR = 15 cm and PQ = 15 cm.

We are to find the length of QR.

Since the adjacent faces of a cube are perpendicular to each other, so the triangle PQR will be a right-angled one with ∠PQR = 90° and PR is the hypotenuse.

Therefore, using the Pythagoras theorem, we get

$PQ^2+QR^2=PR^2\\\\\Rightarrow QR^2=PR^2-PQ^2\\\\\Rightarrow QR=\sqrt{15^2-7.5^2}\\\\\Rightarrow QR=\sqrt{225-56.25}\\\\\Rightarrow QR=\sqrt{168.75}\\\\\Rightarrow QR=12.99.$

That is, QR = 13 cm (rounding to the nearest tenth).

Thus, the  length of the diagonal of a face of the cube is 13 cm.

Option (C) is CORRECT.