21. if Sam's erasers are represented by x, then sari, who has three times more, would be represented by 3x. since you are adding two together to get 28, the equation would be 28=3x+x. Simplify to 28=4x, divide by 4 to isolate x, where x=7. multiply this by 3 to get sari's amount.
The required percentage error when estimating the height of the building is 3.84%.
<h3>How to calculate the percent error?</h3>
Suppose the actual value and the estimated values after the measurement are obtained. Then we have:
Error = Actual value - Estimated value
Given that,
An estimate of the height, H meters, of a tall building can be found using the formula :
H = 3f + 15
where the building is f floors high.
f = 85
The real height of the building is 260 m.
H = 3f + 15
Put f = 85 in the above formula
H = 3(85) + 15
H = 270 m
Error,

So, the required percentage error is 3.84%.
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Answer:
18 in
Step-by-step explanation:
First you would multiply 2·5=10 then for the area of the bottom shape you already have 4 for one side to get the other side you subtract 7-5 and get 2 so 4·2=8 so then add the areas of both shapes and get 18
Answer:
option B
Step-by-step explanation:
Top right graph
Answer:
SAS
Step-by-step explanation:
well there exactly ths same you just add what ever inside and subtract forn 180 which is an angle