This is a right triangle. To find the length of the hypotenuse a^2 + b^2 = c^2.
21^2 + 18^2 = c^2
441 + 324 = c^2
765 = c^2
27.66 km
Evidence are simply facts to support a claim, while counterexamples are instances to show the contradictions in a claim
<em>The question is incomplete, as the required drop-down menus are missing. So, I will give a general explanation</em>
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To show that a statement is true, you need evidence.
Take for instance:

The evidence that the above proof is true is by taking the <em>squares of both sides of </em>


However, a counterexample does not need a proof per se.
What a counterexample needs is just an instance or example, to show that:

An instance to prove that:
is false is:

Hence, the complete statement could be:
<em>In a direct proof, evidence is used to support a proof
. On the other hand, a counterexample is a single example that shows that a proof is false.</em>
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Read more about evidence and counterexample at:
brainly.com/question/88496
Based on the elements and charges in Copper (II) Oxalate, CuC₂O₄(s), the solubility in pure water is 1.7 x 10⁻⁴ M.
<h3>What is the solubility of Copper (II) Oxalate in pure water?</h3>
The solubility equilibrium (Ksp) is 2.9 x 10⁻⁸ so the solubility can be found as:
Ksp = [Cu²⁺] [C₂O₄²⁻]
Solving gives:
2.9 x 10⁻⁸ = S x S
S² = 2.9 x 10⁻⁸
S = 1.7 x 10⁻⁴ M
Find out more on solubility at brainly.com/question/23659342.
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