Answer:
see explanation
Step-by-step explanation:
The perimeter is the sum of the 3 sides, that is
perimeter = 8 + 12 + 17 = 37 cm
To use Heron's formula for area (A)
A =
where a, b and c are the lengths of sides and s the semi perimeter
s = 37 ÷ 2 = 18.5
let a = 8, b = 12 and c = 17, then
A =
=
= ≈ 43.52 cm² ( to 2 dec. places )
Answer:
Step-by-step explanation:
The formula that is used to calculate the area of a rectangle is:
Where "l" is the lenght and "w" is the width.
You know that the area of that rectangle is:
And, according to the exercise, its lenght is 7 more than its width; then:
Then, you can make the corresponding substitution into the formula :
Simplify:
Factor the equation. Find two numbers whose sum is 7 and whose product is -744. These are 31 and -24.
Then, you get:
The width of the rectangle is the positive value:
Then, the lenght is: