Answer:

Step-by-step explanation:
we know that
Heron's Formula is a method for calculating the area of a triangle when you know the lengths of all three sides.
so

where
a, b and c are the length sides of triangle
s is the semi-perimeter of triangle
we have

Find the semi-perimeter s

Find the area of triangle



Simplify

The 3 angles of a triangle, when added, = 180 degrees
so if 2 of them are 70.....70 + 70 = 140
then the 3rd will be 180 - 140 = 40 degrees <==
For the first part
5 an hour plus 50
Can you make an equation out of it
Answer: B. d - 0.2
Step-by-step explanation: 20%= 20/100= 0.2
Which means = d-0.2
Hope this helped.
Let the actual value of the stool be x.
So if the carpenter sells the stool x rupees he neither loses, now wins anything.
67.50 is the value x - 10% of x, that is:
67.50=x-0.1x
67.50=0.9x
x=67.50/0.9=75 (rupees) is the actual value of the stool.
Selling the stool for 82.50 rupees, the carpenter clearly would make a profit, say of y% of that actual value, that is y%*75.
So using the same method:
82.50=75+y%*75
y%*75=82.50-75=7.5
we can make the calculations, but clearly 7.5 is 10% of 75
Answer: 10% gain.