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3 years ago

NEED HELP ASAP!!!!!!!!!!!

Mathematics

1 answer:

Ivanshal [37]3 years ago

4 0

Answer:

a. $\frac{x + 3}{21}=\frac{x + 1}{15}$

b. x = 4 (see steps below)

Step-by-step explanation:

Since the two polygons are similar, the sides are proportional to each other. Using a proportion, you can solve for 'x' using cross-multiplication and division:

$\frac{smaller}{larger}=\frac{x + 3}{21}=\frac{x + 1}{15}$

Cross-multiply: 15(x + 3) = 21(x + 1)

Distribute: 15x + 45 = 21x + 21

Subtract '15x' from both sides: 15x + 45 - 15x = 21x + 21 - 15x or 45 = 6x + 21

Subtract '21' from both sides: 45 - 21 = 6x + 21 - 21 or 24 = 6x

Divide by 6 on both sides: 24/6 = 6x/6

Solve for x: x = 4

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How to find the answers ?

maria [59]

AD || BC and BD is the transversal,

Therefore, angle DBC = angle ADB = 42° [alternate angles]

AD || BC and BD is the transversal,

angle BAD + angle ABD + angle DBC = 180° [co-interior angles]

or, 106°+ angle ABD + 42° = 180°

or, 148° + angle ABD = 180°

or, angle ABD = 180°-148° = 32°

Therefore, angle ABC = (32+42)° = 74°

AB||CD and BC is the transversal,

angle ABC + angle BCD = 180° [co-interior angles]

or, 72+2x+12 = 180

or, 84+2x = 180

or, 2x=180-84 = 96

or, x = 48

Answers: a)48°

b)42°

c)72°

3 0

2 years ago

-34-r=-7(8r-3) what is the work and answer

NeX [460]

-34-r=-7(8r-3)
- 34 - r = - 56r + 21
- r + 56r = 21 + 34
55r = 55
r = 55/55
r = 1

5 0

3 years ago

WILL mark brainliest!

Angelina_Jolie [31]

Answer:

110.5348 minutes

Step-by-step explanation:

The difference from room temperature changes from 103 to 59 in 46 minutes, so that difference can be modeled by the exponential equation ...

Δt = 103×(59/103)^(t/46)

We want to find t for the temperature difference Δt = 91 -64 = 27.

27 = 103×(59/103)^(t/46)

27/103 = (59/103)^(t/46) . . . . . divide by 103

Taking logs gives the linear equation ...

log(27/103) = (t/46)log(59/103)

Multiplying by the inverse of the coefficient of t, we get ...

t = 46·log(27/103)/log(59/103) ≈ 46·(-0.58147346)/(-0.24198521)

≈ 110.5347

It will take about 110.5347 minutes for the turkey to cool to 91 °F internally.

_____

Comment on 4 decimal places

An answer correct to 4 decimal places (7 significant digits) is a pretty good indication that the problem was worked correctly. However, that level of precision in the timing makes little sense in this context. Most thermometers will take at least a few seconds to register the temperature to within a tenth of a degree or so. This problem is asking for an answer that is within 6 milliseconds and 30 micro-degrees. Neither of these is anywhere near realistic for a kitchen meat thermometer.

More realistic would be an answer to 4 significant figures, a tenth of a minute and a few hundredths of a degree.

(The rate of change at the time of interest is about -0.33 degrees per minute.)