Arock outcrop was found to have 95.82% of its parent u- 238 isotope remaining. approximate the age of the outcrop. the half-life of u- 238 is 4.5 billion years old.
a) 277 million years
b) 1.7 billion years
c) 14 million years
d) 21 million years

A) 277 million years

Step-by-step explanation:

Here, decay of U-238 is first order reaction. (since most of the nuclear decays are first order).

so, the equation t = × ln()

where, t = time from start of reaction

           k = reaction constant

           A(0) = initial concentration; A = present concentration.

     ⇒ 4.5 billion = 4500 million years = × ln2.

Now, given 95.82% of parent U-238 isotope is left.

⇒ t = × ln()

  t = × ln()

⇒ t ≅ 277 million years.

1.0

step-by-step explanation:

∠lno ≅ ∠lnm

∠oln ≅ ∠mln

step-by-step explanation:

given   that triangle lno is congruent to triangle lnm.

we have to fill up the blanks in the given question.

according to above order of congruency   kept in mind we can say that

∠lno ≅ ∠lnm

∠oln ≅ ∠mln

ln ≅ ln due to common in both.

hence, by sas congruency,

the side angle side rule   states that if two sides and the included angle of one triangle are congruent to another triangle, then these two triangles are congruent.