A = (1/2) b * h
h = b - 5
42 = (1/2) * b * (b - 5)
42 = (1/2) * b^2 - 5b
multiply both sides by 2 to clear the fraction (1/2)
2(42) = 2(1/2) *b^2 - 5b
84 = b^2 -5b
Since this is a quadratic equation, subtract 84 from both sides so that it is set = to zero.
b^2 - 5b - 84 = 0
Now factor.
(b - 12)(b + 5) = 0
b - 12 = 0; b = 12
b + 5 = 0; b = -5
You can't have a negative length so the answer is 12m
To check the answer:
A = (1/2) * 12* 7
A = 42 m^2
Answer:
The length of side AC is 5 units.
The areas of triangle ABC is 10 square units.
Step-by-step explanation:
From point A (1,3) to point C (1,-2) is 5 units
To check this:
3 - (-2) = 3 + 2 =5
We're subtracting since the point went down (from positive 3 to negative 2)
Now for the area:
Area formula for a triangle:
bh =
⋅b⋅h
We already found the height (length) : 5
The base is from point C (1,-2) to point B (5,-2), which is 4 units
To check this:
5 - 1 = 4
Now that we have found the base and height, Let's solve:
⋅4⋅5 =
⋅20 = 10
Our area is 10 square units.
Hope that helps :)
Im not good at this, thought Ive done Geometry, But for the first one (180-70) which should be 110, and for the second one I would say 55.
Answer:
Step-by-step explanation:
65% of 80 is
65*80/100=52