Answer:
(4.29×10¹⁵)⋅(1.96×10⁻⁴) = 8.40 × 10¹¹, has three significant digits.
Step-by-step explanation:
To solve: (4.29×10¹⁵)⋅(1.96×10⁻⁴)
According to the product rule of exponents, when exponents having the same base are multiplied, the base is kept the same and the powers are added.
Therefore,
(4.29×10¹⁵)⋅(1.96×10⁻⁴) = (4.29 × 1.96) · 10⁽¹⁵⁻⁴⁾ = 8.40 × 10¹¹
The number, 8.40 × 10¹¹ has three significant digits.