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3 years ago

HELPPPPPPPPPPP

Mathematics

1 answer:

liubo4ka [24]3 years ago

3 0

(A) Find the approximate length of the plank. Round to the nearest tenth of a foot.
Given that the distance of the ground is 3ft.
In order to get the length of the plank,
we can use the this one.

cos 49 = ground / plank
cos 49 = 3 / plank
plank = cos 49 / 3
plank = 0.10 ft

(b) Find the height above the ground where the plank touches the wall. Round to the nearest tenth of a foot.

The remaining angle is equal to
angle = 180 - (90+49)
angle = 41

Finding the height.
tan 41 = height / ground
tan 41 = height / 3
height = tan 41 / 3
height = 0.05 ft.

(A) 0.10 feet
(B) 0.05 feet

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Step-by-step explanation:

I'm not quite sure if I'm doing this right myself but I'll give it a shot.

We use this formula to find half-life but we can just plug in the numbers we know to find t.

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$74=100(1/2)^t^/^5^7^3^0$

Now, solve. First, divide by 100.

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Take the log of everything

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Divide the entire equation by log (0.5) and multiply the entire equation by 5730 to isolate the t and get

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