Why is it to estimate the answer before adding or subtracting decimals?

So you can get a basic idea of what your actual answer will be in range of.

Example:
10.5+5.5=__

I can safely assume with estimating that it'll be 15.
Now when I actually find the correct answer which is 16, its a safe bet knowing that your estimate is close to your actual answer.

If you make an uneducated guess like saying 10.5+5.5 was 30 then your answer was 16 its makes you wonder how you got an estimate of almost 2x of 16.

Estimates help, so you know what range your real answer would be in.

Hope this helps

Intersecting secant-tangent theorem states that if a tangent segment and a secant segment are drawn to a circle from an exterior point, then the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.so to break it down: 1. pq acts as the tangent and ps as the secant with an intersection at p.sr = 21rp = 3x + 3pq = 4x + 4following to equation: tangent squared = the two segments multiplied by each otherso (4x + 4) ^ 2 = (3x + 3) • (21) simplifies to 16x^2 - 31x - 47 = 0 or (16x - 47)(x + 1) x = -1 or x = 47/162. pq acts as the tangent and ps as the secant with an intersection at p (again! )sr = 16rp = xpq = 15(15) ^ 2 = 16 • x225 = 16xx = 225/163. the interesting chords are proportional to each other so a ratio is possible to set up: ap dp 10 3 + x = = —— = pc pb 8 xcross multiple to get 10x = (3 + x)(8)x = 12