Aidan has four cards with +, -, x, ÷ printed on them. He inserts them between the five numbers 5, 4, 3, 2 and 1 to form the expression 5 + 4 x 3 -2 , which the value 15.

Emma says:

"Aidan put the operation in the order +, -, x, ÷.
If I place the operation cards in a different order between the number 5, 4, 3, 2, 1. I can make the value equal to 19."

Which operation would Emma do first?

9514 1404 393

  multiply (×)

Step-by-step explanation:

5 ×4 - 3 +2 ÷1 = 19

Emma would place the multiply (×) operation first.

The proof is mentioned below.

Step-by-step explanation:

Here, Δ ABC is isosceles triangle.

Therefore, AB = BC

Prove: Δ ABO ≅ Δ ACO

In Δ ABO and Δ ACO,

∠ BAO ≅ ∠ CAO  ( AO bisects ∠ BAC )

∠ AOB ≅ ∠ AOC ( AO is perpendicular to BC )

BO ≅ OC ( O is the mid point of BC)

Thus, By ASA postulate of congruence,

Δ ABO ≅ Δ ACO

Therefore, By CPCTC,

∠B ≅ ∠ C

Where ∠ B and ∠ C are the base angles of Δ ABC.