That's a question about the Pythagorean Theorem.
We use the Pythagorean Theorem to find the value of one side in a right triangle.
This theorem says that:

- <em>a</em> is the hypotenuse (It's the opposite side the right angle).
- <em>b</em> and <em>c </em>are cathetus (They're the adjacent sides the right angle).
Okay, now, let's go to solve this problem! In our figure, we have two cathetus. Their values are 10 and 7 and we have to find the value of <em>x </em>(the hypotenuse). Let's change this information in that formula.

Therefore, the value of <em>x </em>is
.
I hope I've helped. :D
Enjoy your studies! \o/
Answer: 548.8 square inches
Step-by-step explanation:
From the question, we are informed that a cereal box has a surface area of 280 square inches.
The surface area of a similar box that is larger by a scale factor of 1.4 will be gotten by multiplying 280 by the scale factor's square. This will be:
= 280 × (1.4)²
= 280 × 1.96
= 548.8 square inches