For part (a) the answer is 400 grams for part (b) 198.63 grams and for part (c) 20 years.
<h3>What is exponential decay?</h3>
During exponential decay, a quantity falls slowly at first before rapidly decreasing. The exponential decay formula is used to calculate population decline and can also be used to calculate half-life.
We have an equation for radioactive decay:

a) Plug t = 0

m(0) = 400 grams
b) plug t = 20 years

After solving:
m(20) = 198.63 grams
c) Plug m(t) = m(0)/2 = 400/2 = 200 grams

x = 19.80 years ≈ 20 years
Thus, for part (a) the answer is 400 grams for part (b) 198.63 grams and for part (c) 20 years.
Learn more about the exponential decay here:
brainly.com/question/14355665
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Answer:
Step-by-step explanation:
<h3>Given</h3>
<h3>To find</h3>
<h3>Solution</h3>
- tan (2pi - x) =
- - tan (x) =
- - 2/5
Correct choice is B
Answer:
13.9cm
Step-by-step explanation:
13^2 = 169
5^2 = 25
169 + 25
= 194
13.9
wouldn't it just be because 26 i greater then 25 there for aking 26x93 greater then 25x93
Answer: 54 cm²
Step-by-step explanation: In this problem, we're asked to find the area of the trapezoid shown. A trapezoid is a quadrilateral with one pair of parallel sides.
The formula for the area of a trapezoid is shown below.

The <em>b's</em> represent the bases which are the parallel sides and <em>h</em> is the height.
So in the trapezoid shown, the bases are 6 cm and 12 cm and the height is 6 cm. Plugging this information into the formula, we have
.
Next, the order of operations tell us that we must simplify inside the parentheses first. 6 cm + 12 cm is 18 cm and we have
.
is 9 cm and we have 9 cm · 6 cm of 54 cm²
So the area of the trapezoid shown is 54 cm².