Упр.15 Appendix 1 Математика ГДЗ Enjoy English 10 класс
Work in small groups. Read Jerry’s message and solve his problem.
a) Use the laws of geometry and write down your solution.
b) Explain to Jerry (and to the whole class) your way of solving the problem. Choose the group which presented and explained the solution the most clearly.
Hi! I was told to buy a special acid-resistant floor covering for our chemical laboratory. This floor covering is very expensive and I need to know the exact quantity, i.e. how many square metres to buy. The problem is that there’s lots of chemical equipment in the lab at the moment, and I’m not allowed to touch anything. So, I can measure the length of the lab — it’s 12 metres, but can’t measure its width. I can also measure the distance from the door corner to the window corner (it’s 13 metres), but it doesn’t seem to help much, does it? I need help! I don’t want my boss to think that I’m stupid and fire me!
Call me as soon as possible,
Jerry
Jerry can find the width of the lab using the Pythagorean theorem.
If the lab is rectangular, then the length, width and diagonal form a right triangle:
12² + x² = 13²
x² = 169 — 144 = 25
x = 5
So, the width of the lab is 5 metres.
Now we can find the area:
12 × 5 = 60
Jerry needs to buy 60 square metres of floor covering.
He can explain it like this: the lab is a rectangle, so the diagonal, length and width make a right triangle. Knowing the length and the diagonal, we can calculate the width with the Pythagorean theorem, and then find the area of the floor.
